To see the other types of publications on this topic, follow the link: Potato virus Y. Potatoes.
Dissertations / Theses on the topic 'Potato virus Y. Potatoes'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Potato virus Y. Potatoes.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Barbar, Aqeel Nazzal. "Genetic and molecular analysis of resistance to Potato virus Y and Potato virus S in potato (Solanum tuberosum)." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=201847.
Full text
2
Davey, Triona. "The importance of potato mop-top virus (PMTV) in Scottish seed potatoes." Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2300.
Full textAbstract:
The key aim of this research was to determine the extent of PMTV infection in Scottish seed potatoes and the critical factors which influence infection. The research incorporated a survey of PMTV infection in susceptible cultivars in Scotland, a glasshouse trial to determine the role of temperature in the transmission of PMTV from the soil to the host plant, and field trials which studied the transmission rate from seed to daughter tubers and the relative contribution of seed and soil inoculum to disease development. The survey of Scottish seed crops showed that PMTV occurs in all regions of Scotland but is not particularly prevalent even on known susceptible cultivars. The incidence of crops infected by PMTV differed greatly amongst the regions, with more crops grown in Central Scotland being infected than elsewhere. Although the occurrence of PMTV is linked to the powdery scab organism, there is no correlation between the occurrence of powdery scab and PMTV infection. Temperature was found to be an important factor in the occurrence of symptoms of PMTV infection. The incidence of PMTV infection in tubers was similar at 12°C and 19°C but spraing was absent at 19°C. Transmission from seed to daughter tubers was found to be inefficient, with less than half the daughter tubers derived from PMTV-infected seed being infected by PMTV. However, high incidences of tuber infection were often present in crops after one growing season indicating that soil inoculum is the main source of PMTV infection. Seed-borne inoculum is also of great importance as planting infected seed tubers in clean land brings a risk of introducing PMTV into the soil.
3
MacKenzie, Donald J. "Molecular characterization of potato virus S and genetic engineering of virus resistant plants." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30622.
Full textAbstract:
The sequence of 3553 nucleotides corresponding to the 3'-terminal region of potato virus S (PVS) has been determined from cloned cDNA. The sequence obtained contains six open reading frames with the potential to encode proteins of Mr 10,734, Mr 32,515, Mr 7,222, Mr 11,802, Mr 25,092 and at least Mr 41,052. The amino acid sequence of the 33K ORF has been confirmed to be that of the viral coat protein gene. The nucleotide sequence of this ORF was obtained from expression plasmids which were isolated by binding with a specific monoclonal antibody to PVS, and the expression of coat protein fusion products was verified by Western blots of bacterial cell lysates. The deduced amino acid sequence of a 70 amino acid portion from the central region of the PVS coat protein was 59% identical to the analogous region of potato virus X. In addition, the 7K, 12K and 25K ORF's displayed significant sequence homology with similar sized ORF's from a number of potexviruses. The partial 41K ORF was homologous with the C-terminal portion of the viral replicase proteins of potato virus X and white clover mosaic virus. While the biological functions of the 12K and 25K non-structural proteins coded for by PVS and members of the potexvirus group remain unknown, the 12K protein displays a hydropathicity profile consistent with a membrane associated protein and the 25K protein contains a conserved sequence motif found in a number of nucleoside triphosphate binding proteins. Members of the carlavirus group are distinguished from the potexviruses by the presence of a small [11K (PVS, potato virus M) - 16K (lily symptomless virus)] 3' terminal ORF which appears to contain a sequence motif similar to the 'zinc-finger' domain found in many nucleic acid binding proteins.
The coat protein gene from potato virus S (PVS) was introduced into Nicotiana debneyii tobacco as well as a commercial potato cultivar, 'Russet Burbank', by leaf disc transformation using Agrobacterium tumefaciens. Transgenic plants expressing the viral coat protein were highly resistant to subsequent infection following mechanical inoculation with the Andean or ME strains of PVS as indicated by a lack of accumulation of virus in the upper leaves. The coat protein mediated protection afforded by these transgenic plants was sufficient to prevent the accumulation of virus in the tissues of non-transformed 'Russet Burbank' shoots which had been grafted onto transgenic plants inoculated with PVS, and in reciprocal grafts, transgenic shoots accumulated less than 2% (6 weeks after grafting) of the concentration of PVS found in non-transformed shoots similarly grafted onto plants systemically infected with PVS. These transgenic plants also displayed a measure of resistance to inoculation with a related carlavirus from potato, potato virus M. In agreement with previous reports for plants expressing PVX coat protein, plants expressing PVS coat protein were also protected from inoculation with PVS RNA. These results provide further evidence that coat protein mediated protection for these two groups of viruses, which share similar genome organizations, may involve inhibition of some early event in infection, other than, or in addition to, virus uncoating.
Specific monoclonal antibodies were prepared against a C-terminal derived 18 kDa portion of the 25K protein of PVS expressed as an in-frame chimeric fusion protein with the glutathione S-transferase gene. The in vivo expression of this non-structural protein in virus infected tissue, as well as tissue from transgenic tobacco (var Xanthi-nc) engineered to contain the entire 25K gene, was verified by Western immunoblot labelling.<br>Medicine, Faculty of<br>Biochemistry and Molecular Biology, Department of<br>Graduate
4
Oruechevarria, Igor. "Replication and genetic variability in the genus Potyvirus : studies on Potato virus V and Potato virus A /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5806-4.pdf.
Full text
5
Akiew, E. B. "Potato diseases in South Australia : studies in leafroll, early blight and bacterial wilt /." Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09pha315.pdf.
Full text
6
Rothmann, Adri Hilda. "An assessment of the mutation patterns in South African isolates of Potato leafroll virus and the expression of recombinant viral coat protein genes in Escherichia coli." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19861.
Full textAbstract:
Thesis (MSc)--University of Stellenbosch, 2007.<br>ENGLISH ABSTRACT: Presently, the observed variation in symptoms of Potato leafroll virus (PLRV) infection in potato
cultivars in South Africa cannot be reconciled with PLRV symptoms obtained 10-15 years ago,
even if the different interactions between the pathogen and the cultivar are taken into account.
In an effort to analyze this variation, mutations in the coat protein (CP) gene of South African
isolates of PLRV were assessed. The CP gene of PLRV isolates from different areas within
South Africa was amplified by reverse transcription-polymerase chain reaction (RT-PCR),
cloned and sequenced. Significant sequence variation in the CP gene was found within the
analyzed South African isolates of PLRV. Phylogenetic analysis revealed two major clades with
most South African isolates and an Australian and North American isolate grouped together and
the remainder grouped with isolates from diverse countries worldwide. The deduced amino acid
sequences from representatives of these two clades indicated differences in CP threedimensional
structure.
In an effort to produce recombinant PLRV CP for the production of antibodies specific for South
African isolates of PLRV for use in enzyme-linked immunosorbent assay (ELISA), the CP gene
of a South African isolate of PLRV was subcloned into a bacterial expression vector (pET14-b).
Expression of full length recombinant PLRV CP was attempted in Escherichia coli strains
BL21(DE3)pLysS, Rosetta-gami B(DE3)pLysS and Rosetta-2(DE3)pLysS. As this was not
successful, the PLRV CP gene was subcloned in another expression vector (pGEX) for
expression as an N-terminal fusion protein with glutathione-S-transferase (GST) in E. coli
strains BL21(DE3)pLysS and Rosetta-2(DE3)pLysS. The recombinant GST-PLRV CP fusion
protein was purified and used for antibody production in rabbits. Using western blots, the
effectiveness of antibodies produced to recombinant GST-PLRV CP fusion protein was
assessed for PLRV recognition. It was found that antibodies to the recombinant GST-PLRV CP
fusion protein were more effective for the detection of GST than PLRV CP and that production
of antibodies to the cleaved PLRV CP product would be necessary if antibodies are required for
ELISA applications.<br>AFRIKAANSE OPSOMMING: Huidiglik kan die waargeneemde simptome van infeksie met aartappelrolbladvirus (Potato
leafroll virus, PLRV) in aartappelkultivars in Suid-Afrika nie vereenselwig word met PLRV
simptome wat 10-15 jaar gelede verkry was nie, selfs al word die verskillende interaksies tussen
die patogeen en kultivar in ag geneem.
In ‘n poging om hierdie variasie te analiseer, was mutasies in die mantelproteïen (CP) geen van
Suid-Afrikaanse isolate van PLRV bepaal. Die CP geen van PLRV isolate van verskillende
areas in Suid-Afrika was ge-amplifiseer met behulp van die tru transkripsie-polimerase ketting
reaksie (RT-PCR), gekloneer en die nukleotiedvolgorde bepaal. Noemenswaardige nukleotied
variasie is in die CP gene van die ge-analiseerde Suid-Afrikaanse isolate van PLRV gevind.
Filogenetiese analises het gedui op twee hoof klades met die meeste van die Suid-Afrikaanse
isolate wat saam met ‘n Australiese en Noord-Amerikaanse isolaat gegroepeer en die res wat
met isolate van verskillende lande wêreldwyd gegroepeer. Die afgeleide aminosuurvolgordes
van verteenwoordigers van bogenoemde twee klades het gedui op verskille in die CP driedimensionele
struktuur.
In ‘n poging om rekombinante PLRV CP te produseer vir die produksie van antiliggame
spesifiek teen Suid-Afrikaanse isolate van PLRV om in “enzyme-linked immunosorbent assay”
(ELISA) te gebruik, was die CP geen van ‘n Suid-Afrikaanse isolaat van PLRV gesubkloneer in
‘n bakteriële ekspressie vektor (pET14-b). Daar was gepoog om vollengte rekombinante PLRV
CP in die Escherichia coli rasse BL21(DE3)pLysS, Rosetta-gami B(DE3)pLysS en Rosetta-
2(DE3)pLysS te produseer. Aangesien dit nie suksesvol was nie, was die PLRV CP
gesubkloneer in ‘n ander ekspressie vektor (pGEX) sodat die proteïen as ‘n N-terminale fusie
proteïen met “glutathione-S-transferase” (GST) in E. coli rasse BL21(DE3)pLysS en Rosetta-
2(DE3)pLysS geproduseer kon word. Die rekombinante GST-PLRV CP fusie proteïen was
gesuiwer en gebruik vir antiliggaam produksie in konyne. Die effektiwiteit van die antiliggame
wat teen rekombinante GST-PLRV CP fusie proteïen geproduseer was vir PLRV herkenning is
deur middel van “western blots” geanaliseer. Dit was gevind dat antiliggame teen die
rekombinante GST-PLRV CP fusie proteïen meer effektief was vir die herkenning van GST as
PLRV CP. Gevolglik sal dit nodig wees om antiliggame teen die gesnyde PLRV CP produk te
maak vir gebruik in ELISA.
7
Lahuf, Adnan. "Host resistance and molecular interaction studies on potato mop-top virus and its vector Spongospora subterranea." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=225758.
Full text
8
Cruz, Simon Santa. "Analysis of resistance to potato virus X in potato." Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359280.
Full text
9
Visser, Johan Christiaan. "A study of genomic variation in and the development of detection techniques for potato virus Y in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/21878.
Full textAbstract:
Thesis (MSc)--University of Stellenbosch, 2008.<br>ENGLISH ABSTRACT: Potato virus Y (PVY) is responsible for considerable yield losses in the South African potato industry.
The incidence of this virus has greatly increased over the past few years. Even more worrying is the
variation of symptoms observed during PVY infection and the recent appearance of the more virulent
PVYNTN strain in local fields. This project aimed to investigate the possible genetic variation within the
viral genome and to establish the origin of strains. The project also aimed to establish a dependable, area
specific enzyme-linked immunosorbent assay (ELISA) to replace the currently used ELISAs. Currently
seed potato certification is done using ELISA kits imported from Europe. These kits were developed for
the detection of overseas variants of PVY and the use thereof in South Africa has in the past lead to false
negatives. Finally, this project set out to develop, optimize and establish a sensitive and reliable real-time
reverse transcriptase polymerase chain reaction (qRT-PCR) detection protocol for PVY.
In the first part of the study the coat protein (CP) gene of PVY isolates from plant material obtained from
various parts of South Africa was amplified using RT-PCR. The resulting cDNA was then sequenced
directly or cloned into a vector and then sequenced. The resulting sequences were aligned in a data matrix
with international reference sequences, analyzed and grouped according to strain. Examination of the CP
gene within this matrix as well as phylogenetic analysis revealed six main groups of PVY. These six
groups included the traditional PVYN and PVYO groups and a recombinant group. Furthermore it also
revealed variants of PVYN and PVYO. These mutants and recombinants pose a threat as they may lead to
South African strains of PVY expressing coat proteins which vary from those found overseas. This may
render the currently used European ELISA method of detection less effective and subsequently result in
an increase in viral prevalence. This reinforced the need for a detection method based on local viral
strains. Phylogenetic and Simplot analysis also confirmed that a recombinant strain between PVYN and
PVYO had evolved and that PVYNTN was such a recombinant.
The second part of the study aimed to develop and establish detection methods based on local variants of
PVY. This included the development of ELISA and qRT-PCR detection methods of PVY. Previously
amplified cDNA of the PVY CP gene was cloned into an expression vector and successfully expressed.
Antibodies produced against the recombinant protein, when used in ELISA, however, failed to achieve
the required levels of sensitivity. This prompted the development of qRT-PCR detection methods for
PVY. Primer combinations for PVY were designed using the previously established CP gene data matrix.
A reliable and sensitive SYBR® Green I based qRT-PCR assay was developed for the detection of PVY.
The assay effectively detected all known South African variants of PVY. Furthermore, a Taqman® assay
was developed for the detection of all variants of PVY. The Taqman® assay was 10 fold less sensitive and
does not allow for amplicon verification through melting curve analysis, but it does add more specificity
due to the addition of the probe. Although these qRT-PCR detection methods are still too expensive to
replace the routine diagnostics done with ELISA, they do offer the opportunity to screen valuable mother
material and confirm borderline cases in seed certification.<br>AFRIKAANSE OPSOMMING: Aartappel virus Y (PVY) is verantwoordelik vir aansienlike opbrengsverliese in die Suid-Afrikaanse
aartappelindustrie. Die insidensie van infeksie deur die virus het drasties toegeneem oor die afgelope jare.
Wat egter meer kommerwekkend is, is die groter variasie in simptome van PVY infeksie en die onlangse
voorkoms ‘n meer virulente ras, PVYNTN. Hierdie projek poog om moontlike genetiese variasie van PVY
te ondersoek en om die oorsprong van rasse op te spoor. Die projek het ook gepoog ook om ‘n bruikbare,
betroubare en area spesifieke “enzyme-linked immunosorbent assay” (ELISA) toets te ontwikkel om die
huidige ingevoerde ELISA te vervang. Hierdie toetse is ontwikkel om oorsese variante van PVY op te
spoor en die gebruik daarvan het in die verlede gelei tot vals negatiewes. Verder is daar ook ondersoek
ingestel na die ontwikkeling van ‘n sensitiewe en betroubare “real-time reverse transcriptase polymerase
chain reaction” (qRT-PCR) protokol vir die opsporing van PVY.
In die eerste deel van die studie is die mantelproteïen geen van PVY isolate vanuit plant materiaal
geamplifiseer deur die gebruik van RT-PCR. Hierdie materiaal is vanaf verskeie streke in Suid-Afrika
ontvang. ‘n Volgordebepalingsreaksie is uitgevoer op gekloneerde of ongekloneerde cDNA verkry uit die
RT-PCR. DNA volgordes is in ‘n data matriks geplaas en vergelyk met internationale volgordes om die
plaaslike isolate te analiseer en te groepeer. Deur vergelyking en filogenetiese ontleding kon ses
hoofgroepe van PVY geïdentifiseer word, wat tradisionele PVYN en PVYO, sowel as ‘n rekombinante ras
en variante binne die tradisionele PVYN en PVYO groepe ingesluit het. Rekombinante en mutante kan
veroorsaak dat Suid-Afrikanse rasse van PVY mantelproteïene uitdruk wat afwyk van die oorsese rasse
wat tot gevolg mag hê dat die ELISAs van oorsee minder effektief kan wees en kan lei tot verhoogde
virus voorkoms. Die realiteit en gevaar versterk die gedagte dat ‘n deteksie metode gebaseer op plaaslike
virusse absoluut krities is. Filogenetiese sowel as Simplot analise het bevestig dat ’n mutante ras tussen
PVYN en PVYO ontstaan het en dat PVYNTN ’n rekombinante ras is.
Die tweede deel van die studie was daarop gemik om deteksie metodes te ontwikkel wat gebaseer was op
plaaslike variante van PVY. Dit sluit die ontwikkeling van ELISA sowel as qRT-PCR deteksie van PVY
in. Voorheen geamplifiseerde cDNA is in ‘n ekspressievektor gekloneer en suksesvol uitgedruk.
Teenliggaampies teen die rekombinante proteïen, indien in ELISA aangewend, kon egter nie die nodige
sensitiwiteit oplewer nie. Dit het aanleiding gegee tot ontwikkeling van qRT-PCR deteksie metodes.
Inleier kombinasies vir PVY was ontwikkel deur die gebruik van die bestaande mantelproteïen geen data
matrikse. ‘n Betroubare en sensitiewe SYBR® Green I qRT-PCR deteksie protokol was ontwikkel vir die
effektiewe deteksie van alle bekende Suid-Afrikanse rasse van PVY. Verder is ‘n sogenaamde
“Taqman®” protokol ook ontwikkel vir deteksie van alle rasse. Die “Taqman®” protokol was 10 voudiglik
minder gevoelig and laat nie bevestiging deur smeltkurwe analise toe nie, maar verleen meer spesifisiteit
deur die toevoeging van die “Taqman® probe”. Hierdie qRT-PCR deteksie metodes is tans te duur om as
roetine diagnostiese toetse te gebruik en kan dus nie ELISA vervang nie, maar hulle bied wel die
geleentheid om waardevolle moeder materiaal te toets en grensgevalle in aartappelsaad sertifisering te
bevestig.
10
Matzopoulos, Mark. "The development of enzyme-linked immunosorbent assays to detect potato virus Y and potato leaf roll virus using recombinant viral coat proteins as antigens." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/16616.
Full textAbstract:
Thesis (MSc)--University of Stellenbosch, 2005.<br>ENGLISH ABSTRACT: Potato Virus Y (PVY) and Potato Leafroll Virus (PLRV) are two of the most destructive
potato viruses capable of drastically diminishing crop yields by up to 80%. The presence of
these viruses in planting material namely seed potato stocks are routinely diagnosed by
enzyme-linked immunosorbent assay (ELISA) kits. The kits currently used by Potatoes South
Africa are obtained from Europe. These kits have produced false positive and false negative
results in the past. Potatoes South Africa required an ELISA that was reliable, cheap and
specific for the detection of South African strains of the two respective viruses.
In this study the viral coat protein genes were amplified by RT-PCR from a South African
source of infected plant material. The PVY and PLRV coat protein genes were subsequently
cloned into pGEM-T Easy vector and sequenced. The sequences of the two viruses were
aligned and compared to corresponding viral coat protein gene sequences obtained from
Genbank. Subsequently the two amplified and cloned coat protein genes of PVY and PLRV
were sub-cloned into an expression system (pET-14b) to induce and express the respective
recombinant viral coat proteins. The induction of the cloned coat protein genes yielded
successful production of the recombinant PVY coat protein but the induction and expression
of the recombinant PLRV coat protein was unsuccessful.
The isolated recombinant PVY CP was then used to immunize a rabbit to produce highly
specific anti-PVY CP immunoglobulins. The antiserum obtained from the rabbit was used to
develop an ELISA to detect the presence of PVY in seed potato stocks in South Africa. The
ELISA kit was subsequently used in preliminary trials to determine if the kit could detect
PVY infected plant material. The initial results of the ELISA trials using PVY infected
material obtained from Potatoes South Africa yielded positive results.<br>AFRIKAANSE OPSOMMING: Aartappel Virus Y (PVY) en Aartappel Rolblad Virus (PLRV) is twee van die mees
vernietigende aartappel virusse wat ‘n oes tot 80% kan verlaag. Virus infeksie van plant
materiaal tewete aartappelmoere word deur “enzyme-linked immunosorbent assay” (ELISA)
toetsstelle bevestig. Die toetsstelle wat op die oomblik gebruik word deur Aartappels Suid-
Afrika word in Europa vervaardig. Hierdie toetsstelle het vals positiewe en vals negatiewe
resultate in die verlede gegee. Aartappels Suid-Afrika benodig toetsstelle wat betroubaar,
goedkoop en spesifiek vir Suid-Afrikaanse virus stamme is.
In hierdie studie is besmette plantmateriaal vanuit Suid-Afrika gebruik vir die amplifisering
van virale mantel proteïen gene met behulp van RT-PCR. Die PVY en PLRV mantel proteïen
gene was daarna in die pGEM-T Easy vektor gekloneer en nukleotied volgordes is bepaal.
Die nukleotied volgordes is met ander PVY en PLRV gene vanaf Genbank vergelyk. Die
twee ge-amplifiseerde en gekloneerde mantel proteïen gene van PVY en PLRV is uitgesny en
gekloneer in ‘n ekspressie sisteem (pET-14b) om die mantel proteïen te produseer. Induksie
van die gekloneerde mantel proteïen gene het gelei tot die suksesvolle produksie van ‘n PVY
mantel proteïen, maar produksie van die PLRV mantel proteïen was onsuksesvol.
Die geïsoleerde PVY mantel proteïen is vervolgens gebruik vir die immunisering van ‘n
konyn vir die produksie van konyn anti-PVY antiliggame. Die antiserum verkry vanaf die
konyn is gebruik vir die ontwikkeling van ‘n ELISA vir die identifisering van PVY infeksies
in aartappelmoere. Voorlopige proewe is deurgevoer om te bepaal of hierdie ELISA PVY
infeksies in plantmateriaal sou kon opspoor. Aanvanklike resultate toon dat die ELISA
suksesvol PVY infeksies in plantmateriaal verkry vanaf Aartappels Suid-Afrika kan opspoor.
11
Forsyth, Alexander Mark. "Resistance to potato virus X specified by the Nb gene of potato." Thesis, University of East Anglia, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294657.
Full text
12
Schroder, Michelle L. "Host plant preference of Rhopalosiphum padi (Hemiptera: Aphididae) and its role in selecting crop border plants to reduce Potato virus Y (PVY) in seed potatoes." Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/79775.
Full textAbstract:
Winged Rhopalosiphum padi in search of good quality host plants transmit the non-persistent
Potato virus Y (PVY) to seed potatoes. Planting a non-virus host plant as a border around the
main crop can reduce PVY incidence, because aphids tend to land in high numbers at the
edge of a field and the crop border acts as a virus sink. Using a trap crop could increase the
number of aphids landing in the border. During host-plant searching behaviour, alate
(winged) aphids respond to short (UV) and long (green - yellow) wavelength stimuli and
plant volatiles. The present study evaluated R. padi preference for maize and wheat cultivars
in comparison to potato cultivars to identify a potential crop border plant that is attractive to
aphids for landing but does not support a high aphid population density. The study further
served to develop selection criteria for potential crop border plants. To this end the landing and settling preference and reproductive rate of R. padi on three cultivars each of maize,
potato and wheat were compared in choice and no-choice laboratory trials. The attractiveness
of different shades of green, relative to differences in spectral reflectance of the crop
cultivars, to R. padi was determined as well as olfactory responses of this species, to the plant cultivars tested. Landing and reproduction of R. padi suggested maize cultivars ‘6Q-121’ and
’78-15B’ are potential crop border plants. In choice and no-choice experiments, R. padi
produced the highest number of offspring on wheat than on maize. In contrast, wheat
cultivars had the greatest potential to be used as crop border plants based on percentage
wavelength reflection in the green-yellow wavelength region. Rhopalosiphum padi preferred
to land on yellow and lime colour targets with a maximum wavelength reflectance of 46%
and 26%, respectively. The peak light reflectance of the crop plants ranged between 12% and
20%, with wheat reflecting the highest percentage of light. However, olfactory responses of
R. padi indicated that maize ‘6Q-121’ may prove to be a suitable crop border plant. The
volatiles emitted by maize ‘6Q-121’ did not contain compounds such as -farnasene, (E)-2- hexenal, indole and TMTT which are known to repel R. padi. On the other hand, R. padi did
not distinguish between maize and wheat cultivars prior to landing, which indicates that both
visual and olfactory cues are important in host plant selection behaviour and thus for
selecting crop border plants. The results of the present study suggest that maize ‘6Q-121’
could be used as a crop border plant in seed potato production regions where R. padi is
abundant, due to high aphid landing and low reproduction rates. In conclusion, a suitable crop
border plant should be a preferred host plant and cultivar of the dominant aphid vector
species in a seed potato production region. Potential plant cultivars should reflect a higher
percentage of light in the green-yellow wavelength region than the main crop and the volatile
profiles should preferably not contain compounds that are known to repel the aphid vector.<br>Thesis (PhD)--University of Pretoria, 2014.<br>Potatoes South Africa (PSA), and the Technology and Human Resources (THRIPP)<br>Zoology and Entomology<br>PhD<br>Unrestricted
13
Wardrop, Elizabeth Ann. "Transmission of potato virus S by aphids." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63934.
Full text
14
Chapman, Sean Nicholas. "A molecular analysis of potato virus X." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386398.
Full text
15
Roberts, Eulian John Foster. "Molecular characterisation of potato yellow mosaic virus." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38145.
Full text
16
Visser, Johan Christiaan. "A study of the strain evolution and recombination of South African isolates of Potato virus Y." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71637.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 2012.<br>ENGLISH ABSTRACT: Potato virus Y (PVY) is responsible for considerable yield losses in the South African potato industry.
The incidence of this virus has greatly increased over the past 20 years. In previous studies nonrecombinant
strains of PVY, PVY N and PVY O, were detected in South African potatoes. In a recent study
the occurrence of non-recombinant strains of PVY in South African potatoes was shown to have
decreased while infection by more virulent recombinant strains, PVY NTN and PVY N-W, had increased
dramatically. Infection of potato plants with PVY may cause stunted growth and mosaic or necrotic leaf
symptoms which in turn can lead to a significant reduction in yield. Highly virulent recombinant PVY
isolates as well as some of the non-recombinant strains may cause potato tuber necrotic ringspot disease
(PTNRD) which may result in losses of 10% to total crop failure. For this reason investigation of
infection by local recombinant isolates on local cultivars was important. To this end a representative
number of isolates were selected for whole genome sequencing based on the relative occurrence of the
various isolates in South Africa. A number of these sequenced isolates were subsequently used to infect
local cultivars of potato in order to investigate the influence of genetic variation within the viral genome
on symptom expression. In this study 27 South African isolates of PVY were sequenced through overlapping RT-PCR fragments.
Seven of these isolates, six PVY NTN and one PVY N-W, were used to mechanically infect four local
cultivars of potatoes under greenhouse conditions. The infected plants were monitored to establish the
rate of systemic spread using a highly sensitive qRT-PCR and resulting tubers were visually screened for
PTNRD. Highly variable recombinant isolates appear to be less virulent than the more conserved
recombinant isolates possibly indicating molecular determinants for pathogenicity. For this reason the
amino acid sequences of the South African isolates were compared to those of international isolates and
scrutinized for variation and substitutions. Some South African isolates displayed amino acid
substitutions unique to the specific isolate, making them unlike those found internationally. Substitution
rates throughout the amino acid sequences differed greatly, with some isolates displaying hardly any
changes whilst others varied a great deal from overseas isolates. Certain regions, many of which had
specific functions, were more conserved than others. This study further investigated the recombination events within the PVY genome using reticulate
phylogenetic analysis, molecular dating and network construction techniques. Unlike existing approaches,
the one described in this study neither assumes an underlying strictly bifurcating species tree nor assumes
prior knowledge of processes underlying deviations between individual gene trees. Through the use of the
resulting robust time calibrated phylogeny, the patterns of diversification and recombination in PVY may
be placed in the historical context of human cultivation of potatoes. Through the use of these techniques
the study aimed to test whether diversification of the major strains of PVY and recombination between
them occurred within the time frame of the domestication and modern cultivation of potatoes. From these
analyses it can be deduced that recombinant strains of PVY were imported into South Africa.<br>AFRIKAANSE OPSOMMING: Aartappel virus Y (PVY) is verantwoordelik vir aansienlike opbrengs verliese in die Suid-Afrikaanse
aartappelbedryf. Die voorkoms van die virus het grootliks toegeneem oor die afgelope 20 jaar. In vorige
studies is nie-rekombinante rasse van PVY, PVY N en PVY O, gedokumenteer in Suid-Afrikaanse
aartappels. 'n Onlangse studie het gevind dat die voorkoms van nie-rekombinante rasse van PVY in Suid-
Afrikaanse aartappels aansienlik gedaal het terwyl infeksie deur virulente rekombinante rasse, PVY NTN en PVY N-W, dramaties toegeneem het. Infeksie van aartappelplante met PVY kan vertraagde groei en
mosaïek- of nekrotiese blaarsimptome veroorsaak wat kan lei tot aansienlike vermindering in opbrengs.
Hoogs virulente rekombinante PVY isolate, sowel as sommige nie-rekombinante rasse, kan aartappel
nekrotiese ring simptome (PTNRD) veroorsaak wat verliese van 10% tot totale misoes tot gevolg kan hê.
Om hierdie rede was die ondersoek van infeksie deur plaaslike rekombinante isolate op plaaslike
kultivare belangrik. Vir hierdie doel is 'n verteenwoordigende aantal isolate gekies, gebaseer op die
relatiewe voorkoms daarvan in Suid-Afrika, vir heelgenoom-volgordebepaling. Van die isolate is
vervolgens gebruik om plaaslike kultivare te besmet ten einde die invloed van genetiese variasie binne die
virale genoom op simptoom uitdrukking te ondersoek.
In hierdie studie is 27 heelgenoomvolgordes van Suid-Afrikaanse PVY isolate bepaal deur oorvleuelende
RT-PCR fragmente. Sewe van hierdie isolate, ses PVY NTN en een PVY N-W, is gebruik om vier plaaslike
aartappel kultivare, gegroei onder kweekhuis kondisies, meganies te infekteer. Die geïnfekteerde plante is
gemonitor om die tempo van sistemiese verspreiding vas te stel deur middel van 'n hoogs sensitiewe qRTPCR
en knolle is visueel inspekteer vir PTNRD. Hoogs variante rekombinante isolate blyk om minder
virulent te wees as die meer bewaarde rekombinante isolate wat dui op molekulêre determinante van
patogenisiteit. Om hierdie rede is die aminosuurvolgordes van die Suid-Afrikaanse isolate vergelyk met
die van internasionale isolate en ondersoek vir variasie en substitusies. Sommige Suid-Afrikaanse isolate
vertoon aminosuur substitusies wat uniek is tot die spesifieke isolaat en maak hul dus anders as
internasionale isolate. Die aantal aminosuursubstitusies in die volgordes verskil grootliks. In vergelyking
met internasionale isolate toon sommige isolate skaars enige veranderinge terwyl ander ‘n aantal verskille
toon. Sekere gebiede, waarvan baie spesifieke funksies het, was meer gekonserveerd as ander.
Hierdie studie ondersoek ook rekombinasie gebeure binne die PVY genoom deur retikulêre filogenetiese
analise, molekulêre datering en netwerk konstruksie tegnieke. In teenstelling met bestaande benaderinge,
aanvaar die tegniek wat hier beskryf word nie ‘n streng bifurkeerende filogenie, wat onderliggende
verdeel, of enige voorafgaande kennis van die prosesse onderliggend aan afwykings tussen individuele
filogenieë nie. ‘n Robuuste, tyd gekalibreer filogenie kan diversifikasie patrone en rekombinasie van PVY
plaas in die historiese konteks van menslike verbouing van aartappels. Deur gebruik te maak van hierdie
tegnieke poog die studie om te toets of diversifikasie en rekombinasie van PVY rasse plaasgevind het
binne die tydsbestek van die inburgering en moderne verbouing van aartappels. Van hierdie ontledinge
word afgelei dat rekombinante rasse van PVY wat in Suid-Afrika voorkom, ingevoer is.
17
Hill, S. A. "An evaluation of potato virus Y and potato leaf roll virus detection in tubers by enzyme-linked immunosorbent assay." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370134.
Full text
18
Sung, Young Kwan. "Functional analysis of potato yellow mosaic geminivirus genes." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321667.
Full text
19
Brigneti, Gianinna. "Molecular and genetical analysis of the Ry-mediated resistance to potato virus Y in potato." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389221.
Full text
20
Harchenko, Whitney Ann. "Marker Assisted Selection Increases the Efficiency of Breeding for Potato Virus Y Resistance in Potato." Thesis, North Dakota State University, 2014. https://hdl.handle.net/10365/27539.
Full textAbstract:
Potato Virus Y (PVY) is an important virus of potato due to the non-persistent mode of transmission by aphids causing yield losses. Genetic resistance is the recommended control since insecticides cannot adequately control the spread of PVY by aphids. The gene Ryadg from S. tuberosum ssp. andigena provides resistance to all strains of PVY. This gene has genetically been mapped to chromosome XI, and linked polymerase chain reaction (PCR) based DNA markers have been identified. This study identified PVY resistant progeny by the use of the molecular sequence-characterized amplified region (SCAR) marker RYSC3. The RYSC3 marker allowed a simple and fast approach to determine if the Ryadg gene was present in the seedling family populations evaluated. The RYSC3 marker identified 16 families with progeny segregating for the Ryadg gene. Progeny segregated 1:1 for PVY resistance, fitting the model simplex (Ryryryry) for the Ryadg allele.
21
Roos, Wiets Gideon. "An investigation of prevalance and the detection and race identification of South African potato viruses." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80313.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: Infection of potatoes by viral pathogens causes reduced crop yield and subsequent economic loss. In
South Africa Potato virus Y (PVY) and Potato leafroll virus (PLRV) are the two most destructive viruses
infecting potatoes. Several other viral pathogens exist, including Potato virus X (PVX), Potato virus M
(PVM), Potato virus A (PVA), Potato virus S (PVS), Potato mop-top virus (PMTV), Tomato spotted wilt
virus (TSWV) and Potato spindle tuber viroid (PSTVd). Although the aforementioned pathogens are
found infecting potatoes around the world, there are no published information pertaining to the prevalence
of these viral agents in South Africa. Currently, the occurrence of PLRV infection in potatoes of South
Africa has reached epidemic proportions. A previous phylogenetic investigation undertaken in our
laboratory of South African PLRV isolates, using coat protein (CP) gene sequences, found large variation
between native South African PLRV isolates and most other isolates from elsewhere in the world; with
their nearest relatives being single isolates from Australia and North America.
In this study the incidence of PVX, PVM, PVA, PVS, PMTV, TSWV and PSTVd was investigated. A
large number of potato plant and tuber samples was collected and infected samples were identified with
reverse transcriptase polymerase chain reaction (RT-PCR) amplification of the CP gene or the whole
genome in the case of PSTVd. The amplified nucleic acid segments were sequenced, aligned with
international reference sequences and analysed phylogenetically to determine their relative relationships
with these reference sequences. The CP genes of PLRV isolates were sequenced and phylogenetically
investigated to determine how these new isolates compared relative to the previous findings from our
laboratory. In addition, the complete genomes of two PLRV isolates were sequenced and phylogenetically
investigated as a preliminary study to investigate the apparent increase of pathogenicity of certain variants
of South African PLRV.
Results obtained showed that only PVX and PVS were present in the samples collected and the
incidences of these viruses were very low (2.0 and 1.1% respectively). The phylogenetic analyses of the
CP genes, indicated that the PVX and PVS variants isolated in this study, were part of the dominant types
of variants found worldwide. From the analyses of the PLRV CP and whole genome sequences, it was
determined that many of the PLRV variants found in South Africa, are genetically distinctly different
from those around the world. This warrants further investigation into the increased pathogenicity
experienced with South African PLRV.<br>AFRIKAANSE OPSOMMING: Infeksie van aartappels deur virale patogene veroorsaak verlaagde opbrengs en gevolglike ekonomiese
verlies. In Suid-Afrika is Aartappelvirus Y (PVY) en Aartappelrolblad virus (PLRV) die twee mees
vernietigende virusse wat aartappels infekteer. Verskeie ander virale patogene, insluitend Aartappelvirus
X (PVX), Aartappelvirus M (PVM), Aartappelvirus A (PVA), Aartappelvirus S (PVS), Aartappel "moptop"
virus (PMTV), Kromnekvirus (TSWV) en Aartappel "spindle tuber" viroïed (PSTVd) kom ook
wêreldwyd in aartappels voor. Alhoewel hierdie virusse aartappels wêreldwyd besmet, is daar geen
gepubliseerde inligting met betrekking tot die voorkoms van hierdie virusse of die viroïed in Suid-Afrika
nie. Tans het die voorkoms van PLRV infeksie in aartappels in Suid-Afrika epidemiese proporsies bereik.
In 'n vorige filogenetiese ondersoek van die mantelproteïen (MP) nukleotiedvolgordes van Suid
Afrikaanse PLRV isolate in ons laboratorium, is groot variasie tussen hierdie inheemse isolate en die
meeste ander isolate van elders in die wêreld bevind. Die Suid Afrikaanse PLRV variante betree 'n unieke
intermediêre posisie tussen die internasionale isolate en enkele isolate van Australië en Amerika.
In hierdie studie is die voorkoms van PVX, PVM, PVA, PVS, PMTV, TSWV en PSTVd ondersoek.
Groot aantal aartappelplant en -knol monsters is versamel en infeksie is getoets met tru-transkripsie
polimerase kettingreaksie (RT-PCR) amplifisering van die MP geen, of die hele genoom in die geval van
PSTVd. Die nukleïensuurvolgordes is bepaal en vergelyk met internasionale verwysingsvolgordes. Die
relatiewe verhoudings tussen die bepaalde volgordes en die verwysingsvolgordes is geanaliseer met
filogeneties ontledings. Die MP gene van PLRV isolate se volgordes is bepaal en filogeneties ontleed om
hierdie nuwe isolate te vergelyk relatief tot vorige bevindinge in ons laboratorium. Die volledige genome
van twee PLRV isolate se volgordes is bepaal en filogeneties ontleed as 'n voorlopige studie om die
oënskynlike toename in patogenisiteit van Suid-Afrikaanse PLRV te ondersoek.
Resultate het getoon dat slegs PVX en PVS teenwoordig was in die monsters wat versamel is en dat die
voorkoms van hierdie virusse baie laag was (2.0% en 1.1% onderskeidelik). Die filogenetiese ontleding
van die MP gene het aangedui dat die Suid Afrikaanse variante van PVX en PVS, geisoleer in hierdie
studie, van die dominante tipes is wat mees gereeld internationaal voorkom. Uit die ontleding van die
PLRV MP en heelgenoom volgordes, is vasgestel dat baie van die PLRV variante wat in Suid-Afrika
aangetref word, geneties meer verskillend is as die van regoor die wêreld. Dus, regverdig dit, verdere
ondersoek van die verhoogde patogenisiteit van Suid Afrikaanse PLRV variante.
22
Hay, Joanne M. "Aspects of the molecular biology of potato virus Y." Thesis, University of Canterbury. Molecular Biology, 1989. http://hdl.handle.net/10092/6649.
Full textAbstract:
Aspects from the coat protein from Potato Virus Y (PVY) were investigated. Polyadenylated, full length RNA was isolated from purified preparations of two strains of the virus, PVYN and PVYC. The RNA was used as a template to produce double stranded complementary DNA (cDNA) which was subsequently cloned into the plasmid vector pUC19. Of the resultant PVYC –derived clones, two recombinant plasmids (pVYC5 and pVYC11) were analysed by DNA hybridlsation and DNA sequencing. PVYC11 contained a viral cDNA insert, while pVYC5 did not.
A recombinant clone containing PVYN cDNA sequences (pVYN27) was characterised by DNA sequencing. The 3'-terminal 1134 nucleotide sequence coded for the coat protein gene and contained one large open reading frame capable of encoding a protein of 264 amino acid residues with a combined molecular weight of 29 631. The ten amino-terminal amino acids of the protein were confirmed by amino acid sequencing.
Transcriptional fusions encoding the PVYN coat protein gene and either the CaMV 35S promoter or the mannopine synthase promoter were inserted into an Agrobacterium binary vector encoding the NPT II gene. These were mobilised into two species of Agrobacterium (A. tumefaciens, LBA4404 and A. rhizogenes, A4T) and transformed into the genomes of Nicotiana plumbaginifolia and Solanum tuberosum. The transgenicity of regenerated tobacco plants was confirmed by 1. the presence of the chimaeric PVYN coat protein gene as demonstrated by DNA hybridisation, 2. expression of the NPT II gene was demonstrated by the regeneration of plants on media containing kanamycin at normally inhibitory concentrations, and 3. demonstration that progeny from transformed plants inherited the NPT II gene in a Mendelian manner. No accumulation of the coat protein by transformants was detected by either Western blots or protein slot blots.
23
Weston, Jonathan Henry. "Expression of the 3'-terminus of potato virus S." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282350.
Full text
24
Ellis, Peter John. "A study of luteoviruses involved in potato leafroll disease." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30803.
Full textAbstract:
In total, 801 samples of potato leafroll disease were collected and tested for potato leafroll virus (PLRV) and beet western yellows virus (BWYV) in 1986, 1987, and 1988 using triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) and virus-specific monoclonal antibodies. The samples represented 32 cultivars and originated in eight Canadian provinces and 12 American states. None of the samples tested positive for BWYV, whereas 772 (96.4%) tested positive for PLRV. Neither PLRV nor BWYV could be recovered, with aphid transfers to indicator hosts, from 28 of the 29 samples that tested negative for both viruses. PLRV was recovered from one sample that originally tested negative by TAS-ELISA; the indicator plant tested positive for PLRV by TAS-ELISA.
Nucleic acid spot hybridization (NASH) using random primed and cloned cDNA probes was compared with double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and TAS-ELISA, and aphid transmission tests for detection and identification of PLRV and BWYV in 165 potato leafroll disease samples. All of the samples tested negative for BWYV with each of the assay procedures. PLRV was detected in all of the samples with TAS-ELISA, NASH with a cloned cDNA probe for PLRV, and with aphid transmission to ground cherry (Physalis
pubescens). Both DAS-ELISA and NASH using random primed cDNA produced one false-negative result. Shepherd's purse (Capsella bursa-pastoris) was a host for 72% (119/165) of the PLRV isolates.
The susceptibility of potato to BWYV was tested by inoculating Russet Burbank with three isolates of BWYV from Canada and four from the United States. Two of the isolates were in a mixed infection with PLRV. None of the isolates were transmitted by Myzus persicae to virus-free potato plants, either by themselves or in association with PLRV.
Common weeds were surveyed in the potato-producing areas of British Columbia for PLRV and BWYV. In total, 10,098 weed samples, representing 98 species in 22 plant families, were collected and tested by TAS-ELISA from 1986 to 1989. BWYV was detected in 1% of the samples; the hosts were: chickweed, common groundsel, heart-podded hoary cress, hedge mustard, little western bittercress, prickly lettuce, shepherd's purse, and wild radish. PLRV was detected in three volunteer potato plants, two samples of shepherd's purse, and one black nightshade plant. The low incidence of PLRV in plants other than potato indicates that weeds are of minor importance in the epidemiology of potato leafroll disease in British Columbia.<br>Land and Food Systems, Faculty of<br>Graduate
25
Sahi, Ghulam Mustafa. "Molecular studies of Tobacco Rattle Virus (TRV) infection in potato." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/22050.
Full textAbstract:
Tobacco rattle virus (TRV) is a bipartite plant virus that infects potato tubers to produce the spraing or corky ring spot (CRS) disease of potato. TRV is primarily a soil-borne pathogen that is vectored by trichodorid nematodes. Spraing is characterized by the production of brown arcs and flecks in the tuber flesh or circular rings on its external surface. Spraing has been described as a hypersensitive response (HR). However, the genetic and biochemical nature of spraing had not been previously investigated experimentally. I have conducted studies to reveal the gene expression and the biochemical basis for spraing formation. Microarray analysis of RNA extracted from tuber-tissue showing spraing symptoms, revealed up-regulation of several defence related genes. Quantitative RT-PCR (qRT-PCR) of some of the differentially-expressed potato defence related genes was done for verification of the microarray data. Biochemical tests for cell death response reactions and staining for HR-related compounds or production of reactive oxygen species (ROS) also revealed the operation of HR-related processes in the spraing-affected tuber. Uneven distribution of the TRV RNA-1 in a spraing-symptomatic tuber also supports the notion that it’s a virus-induced HR-response. RNA-2 of TRV besides coding for the CP also carries the non-structural genes, 2b and 2c genes that are responsible for the nematode transmission of TRV. Fifteen different TRV recombinant isolates were prepared and the influence of the RNA-2 specific genes, encoded by a range of TRV-isolates, in causing infection among different cultivars of potato was also evaluated. Investigations were conducted to identify TRV-susceptible genotypes in which virus could move systemically and accumulate to a sufficient level to be useful for TRV-infection and VIGS-related studies for functional analysis of potato genes.
26
Brandolini, Andrea G. "Breeding potato for resistance to leafroll virus combined with immunity to PVX and PVY." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302990.
Full text
27
Eliasco, Eleonora. "Molecular characterisation of potato yellow vein virus RNAs and associated RNAs." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422680.
Full text
28
Foster, Gary D. "The structure and expression of the genome of potato virus S." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335333.
Full text
29
Osman, Mohamed Hashim. "The molecular basis for Ry gene inhibition of potato virus Y." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282293.
Full text
30
Adams, S. E. "Studies on mechanics and occurrence of resistance of potato virus X." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/37916.
Full text
31
Turner, Róisín L. "Sequences involved in the control of translation in potato virus S." Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/35361.
Full textAbstract:
Specific cis-acting sequences within the carlavirus potato virus S (PVS) genomic RNA molecule appear to control gene expression at the translational level. Two sequences have been investigated, the untranslated sequence upstream from the initiation codon of the viral coat protein gene, designated VTE and the 5' untranslated leader sequence from the genomic RNA molecule (PVS 5'). In vitro and in vivo, either of these sequences enhance the translation of a downstream open reading frame when provided as the untranslated leader in a transcript molecule. Translational enhancement was also detected at the transgenic plant level. Both PVS sequences were deleted in an attempt to identify the core regulatory element responsible for this translational enhancement phenomenon. Results indicate that in vitro and in vivo, the functional motif is contained within the 5' promixal portion of both sequences. When the sequences of these important regions were compared, a homologous block of nucleotides was identified, a block which is also highly conserved within the 5' untranslated leader of another carlavirus, blueberry scorch virus (BBScV). In addition to the function of translational enhancement, the VTE sequence, and a parallel sequence from another carlavirus, Helenium virus S (HelVS), direct internal ribosome entry and initiation of translation in vivo in a prokaryotic system and in vitro in a eukaryotic system, respectively. Results have also indicated that the mechanism of expression associated with the VTE and PVS 5' leader may be at least partially cap-independent in nature. This may represent an adaption by the virus to achieve a maximum rate of translation and multiplication when cellular translational machinery is depleted or altered upon viral infection. Preliminary investigation has also assigned additional functions to both sequences. The VTE sequence may contain the recognition site for the viral polymerase in the production of the PVS 1.3 kb subgenomic RNA molecule. The PVS 5' leader may contain the specific sequence or structure that is recognised by the viral coat protein in the initiation of genomic RNA encapsidation.
32
Davie, Kim. "The biodiversity and epidemiology of potato virus Y (PVY) in Scotland." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27766/.
Full textAbstract:
Potato virus Y (PVY) is considered to be the most serious viral pathogen that affects potato crops worldwide and can cause substantial yield losses. PVY exists as a complex of strains that can be distinguished on the basis of their biology, serology and genome analysis. In recent decades novel recombinant PVYN strains have emerged that can cause Potato Tuber Necrotic Ringspot Disease (PTNRD). It is therefore important to understand the potential threat to the Scottish seed potato industry. This molecular nature of PVY isolates in Scotland was established through the use of partial sequencing, revealing a predominance of isolates belonging to the molecular EU-NTN clade (ca 75%). Assessing the biological characteristics of selected isolates indicated that most isolates in Scotland belong to the biological PVYN type, however PVYE is also present. Molecular analysis of a PVYE isolate has shown that identifying the molecular determinants for vein necrosis production in tobacco is complex. Although it has not been reported from the field in Scotland, PTNRD initiation is possible with most PVYN isolates under optimal climatic conditions. Field trials suggest that PVYEU-NTN is more efficiently transmitted by aphids across a growing season than PVYNA-NTN and PVYO, with a higher than expected proportion of tubers infected with the PVYEU-NTN isolate. This suggests that once plants are inoculated with the virus, PVYEU-NTN isolates are more likely to infect progeny tubers. Taken together, the outcomes of this project should provide a better understanding as of PVY molecular nature in Scotland its pathogenicity and epidemiology with the view to understanding why PVYN variants have become an important threat for the seed potato industry both in Scotland and worldwide.
33
Hühnlein, Anja [Verfasser]. "Quantitative detection of Potato virus Y and Potato leaf roll virus by real time PCR – a molecular approach with numerous applications in potato research / Anja Hühnlein. Julius Kühn-Institut. Gottfried Wilhelm Leibniz Universität Hannover, Naturwissenschaftliche Fakultät." Quedlinburg : Julius Kühn-Institut, 2016. http://d-nb.info/1104186020/34.
Full text
34
Mozafari-Hashjin, Javad. "Genetic engineering and evaluation of pathogen-derived resistance to potato leafroll virus." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24418.pdf.
Full text
35
Domfeh, Owusu. "Studies on the Management of Potato Mop-Top Virus-Induced Tuber Necrosis." Diss., North Dakota State University, 2015. http://hdl.handle.net/10365/24924.
Full textAbstract:
Tuber necrosis caused by the Potato Mop-top Virus (PMTV) has become one of the most important tuber necrosis diseases in the United States. PMTV is transmitted by the powdery scab pathogen (Spongospora subterranea f.sp subterranea (Sss)) and no effective methods of control are currently available for these pathogens. Potato cultivars have been reported to exhibit natural variability in their reaction to PMTV infection, making cultivar selection a viable management option. This dissertation focuses on finding short to long term strategies for managing PMTV tuber necrosis. In the first study, potato cultivars were assessed for sensitivity to PMTV-induced tuber necrosis in three separate field trials. Results of tuber assessments demonstrated that sensitivity to PMTV-induced tuber necrosis among cultivars follows a continuum of tolerant to sensitive. In the second study, advanced breeding selections of potato were evaluated for sensitivity to PMTV-induced tuber necrosis. The results revealed high variability in PMTV-induced tuber necrosis incidence and severity among selections and identified 17 of them to be tolerant, nine ? moderately tolerant, eight - moderately sensitive, while six were found to be sensitive. Results of the field trials show that russet-skinned cultivars and selections are less sensitive to PMTV tuber necrosis than red-, yellow- and white-skinned types. In the third study, a growth chamber experiment was conducted to investigate the potential of using moisture regime to manage PMTV tuber necrosis. The results showed significant differences in PMTV tuber necrosis and powdery scab infection among moisture regimes. Maintaining soil moisture level at 90% field capacity throughout the season resulted in significantly higher incidence and severity of PMTV tuber necrosis and powdery scab infection than keeping soil at 60% field capacity. The results also show that the potato plant may be susceptible to PMTV-induced tuber necrosis and powdery scab infection throughout the season. The results of these investigations
offer potato growers the option to plant less sensitive cultivars in areas where PMTV and powdery scab exist. This information can be utilized in future breeding efforts to obtain resistant potato cultivars. Useful information on using soil moisture regime as a management strategy for PMTV tuber necrosis has been provided.<br>Northern Plains Potato Growers Association<br>U.S. Potato Board<br>Minnesota Area II Potato Growers
36
Anderson, Gavin Lloyd Franklin. "NUCLEAR IMPORT AND INTERACTIONS OF POTATO YELLOW DWARF VIRUS NUCLEOCAPSID, MATRIX, AND PHOSPHOPROTEIN." UKnowledge, 2014. http://uknowledge.uky.edu/plantpath_etds/12.
Full textAbstract:
Potato yellow dwarf virus (PYDV) is the type species of the genus Nucleorhabdovirus and, like all members of this genus, replication and morphogenesis occurs inside the nuclei of infected cells. Protein localization prediction algorithms failed to identify a nuclear localization signal (NLS) in PYDV nucleocapsid (N) protein, although PYDV-N has been shown to localize exclusively to the nucleus when expressed as a green fluorescent protein (GFP):N fusion in plant cells. Deletion analysis and alanine-scanning mutagenesis identified two amino acid motifs, 419QKR421 and 432KR433, that were shown to be essential for nuclear import and interaction with importin-α. Additional bimolecular fluorescence complementation showed that the PYDV-N-NLS mutants cannot be ferried into the nucleus via interaction with PYDV-P or-M. In contrast, interaction with N-NLS mutants appeared to retard the nuclear import of PYDV-P. Taken together, it was determined that PYDV-N contains the bipartite NLS 419QKRANEEAPPAAQKR433. Similarly, alanine-scanning mutagenesis was performed to determine the regions responsible for the nuclear import of PYDV-M and -P. A non-canonical NLS was identified in PYDV-P, consisting of three regions in the N-terminus of the protein required for nuclear import. PYDV-P does not interact with any Nicotiana benthamiana importins, but was found to interact with importin-α7 and -α9 of the non-host plant Arabidopsis thaliana. Two amino acids of PYDV-M, 225KR226, were found to be critical for nuclear import and interaction with importin-α. In addition, site-directed mutagenesis identified that amino acids 223LL224 of PYDV-M, which are adjacent to the two amino acids identified as responsible for nuclear import, are critical for inducing invaginations of the inner nuclear membrane. Bimolecular fluorescence complementation (BiFC) was then used to identify any differences in localization and interaction caused by the mutations introduced to PYDV-P and -M. The PYDV-P and -M proteins were still able to interact with other PYDV proteins, although the localization of the interaction differs between mutants.
37
Charon, Justine. "Contribution du désordre intrinsèque des protéines aux fonctions impliquées dans le cycle viral et l'évolution adaptative des virus à ARN : étude appliquée au genre modèle Potyvirus." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0373/document.
Full textAbstract:
Les protéines sont des acteurs majeurs dans les processus moléculaires et cellulaires d’un organisme. La remise en question des modalités associées aux fonctions de ces macromolécules a récemment été apportée par le concept de désordre intrinsèque. Celui-ci définit l’absence (transitoire ou permanente) de structure tridimensionnelle de certaines protéines ou régions protéiques comme étant directement liée à leurs fonctions. Chez les virus à ARN, les propriétés des protéines ou régions désordonnées semblent associées aux capacités de ces micro-organismes à détourner la machinerie cellulaire de l’hôte en interagissant avec de multiples partenaires, et à s’adapter aux nombreuses contraintes auxquelles ils doivent faire face en tant que parasites obligatoires. Ce travail porte sur les potyvirus, figurant parmi les pathogènes de plantes les plus dommageables étudiés à ce jour. L'objectif de cette thèse a été d’explorer les fonctions associées au désordre intrinsèque dans le cycle infectieux des potyvirus ainsi que dans le processus d’adaptation. Notre approche a ainsi démontré que : i) le désordre est ubiquitaire chez le genre Potyvirus ; ii) les régions de désordre conservées chez plusieurs protéines de potyvirus semblent être associées à leur(s) fonction(s) pendant l'infection ; iii) les régions désordonnées sont généralement associées à moins de contraintes évolutives, suggérant ainsi leur implication dans les processus adaptatifs des potyvirus ; iv) les régions prédites comme désordonnées semblent privilégier l’apparition de mutations et donc la capacité d’un virus à accumuler de la diversité génétique au cours de l'évolution sur son hôte naturel ; v) ce travail a permis de corréler le taux en désordre de la protéine viral genome-linked (VPg) du Potato virus Y à sa capacité à s’adapter à la résistance récessive pvr23 du piment<br>Proteins are essential actors involved in a majority of molecular and cellular processes. The features associated with the functions of these macromolecules have been recently questioned with the emergence of the intrinsic disorder concept. It defines the transitory or permanent lack of 3D structure in some proteins or regions as directly related to their functions. Among RNA viruses, the properties of disordered proteins may be linked to the ability of these microorganisms to hijack the host machinery by interacting with multiple partners, as well as to adapt to the multiple constraints they must face as obligatory parasites. This work focuses on the Potyvirus genus, which includes some of the most damaging plant pathogens studied to date. The goal of this thesis was to explore the functions associated with intrinsic disorder in the infectious cycle of this viral genus as well as in its process of adaptation. Our studies have shown that i) intrinsic disorder is ubiquitous in potyviruses; ii) intrinsically disordered regions (IDR) of some of potyviral proteins are likely to be associated with important functions for the viral cycle ; iii) IDR are generally less evolutionary constrained, suggesting an adaptive potential of these regions ; iv) predicted IDR seem to favor the appearance of mutations and therefore virus ability to accumulate genetic diversity during its evolution in natural host ; v) an experimental disorder modulation within the Viral genome-linked (VPg) protein has been demonstrated as positively correlated with the adaptive ability of the Potato virus Y to overcome the pvr23 recessive resistance in pepper
38
Perraki, Artemis. "La Rémorine, une protéine végétale impliquée dans la propagation virale ; implication des modifications post-traductionnelles." Thesis, Bordeaux 2, 2012. http://www.theses.fr/2012BOR21997/document.
Full textAbstract:
Les Rémorines (REM) du groupe 1 sont des protéines spécifiques du monde végétale. Malgré leur caractère hydrophile elles sont localisées à la membrane plasmique. La phosphorylation des REM serait potentiellement impliquée dans la signalisation précoce et la défense des végétaux contre les pathogènes. Benschop et al. (2007) détecte AtREM1.3 (Arabidopsis thaliana, groupe 1b) phosphorylée en réponse au traitement par l'éliciteur générale flg22, tandis que Widjaja et al. (2008) a suggéré que la phosphorylation de AtREM1.2 est potentiellement impliquée dans la signalisation précoce à l'infection par Pseudomonas syringae. La fonction précise de la phosphorylation des protéines REM du groupe 1 reste inconnue. Des travaux antérieurs dans le laboratoire ont montré que le mouvement du virus X de la pomme de terre (PVX) est inversement corrélée à l'accumulation de StREM1.3 (Solanum tuberosum) et que StREM1.3 peut interagir physiquement avec la protéine de mouvement TRIPLE GENE BLOC Protein 1 (TGBp1) du PVX (Raffaele et al., 2009). Dans ce travail, nous avons étudié les mécanismes qui sous-tendent les interactions REM-TGBp1 et nous avons essayé de caractériser biochimiquement la kinase qui phosphoryle REM. Les conséquences physiologiques de l'interaction TGBp1 / StREM1.3 et de la phosphorylation de REM en terme de propagation des virus, d’inactivation génique post-transcriptionnelle, de régulation de l’ouverture des plasmodesmes, et d’activation de kinase ont également été étudiés<br>The group 1 Remorin (REM) proteins are plant-specific oligomeric proteins that have been reported to localize to the plasma membrane despite their overall hydrophilic nature. There is evidence that the REM protein phosphorylation is potentially implicated in the early signaling and defense. Benschop et al. (2007) detected the AtREM1.3 (Arabidopsis thaliana group 1b of REM protein family) to be phosphorylated in response to treatment with the general elicitor flg22, while the Widjaja et al. (2008) suggested that the phosphorylation of AtREM1.2 is potentially implicated in early signaling upon infection with Pseudomonas syringae. The precise exact function of the group 1 REM protein phosphorylation remains unknown. Previous work in the laboratory showed that Potato virus X (PVX) movement is inversely correlated to potato StREM1.3 accumulation and that StREM1.3 can physically interacts with the movement protein TRIPLE GENE BLOCK PROTEIN 1 (TGBp1) from PVX (Raffaele et al., 2009). In this work, we studied the mechanism underlying the REM-TGBp1 interactions and we tried to characterise biochemically the kinase that phosphorylate REM. The physiological consequences of TGBp1/ StREM1.3 interaction and REM phosphorylation in terms of virus spreading, post-transcriptional gene silencing, plasmodesmata gating, kinase activation were also investigated
39
Rimkevičiūtė, Jurgita. "Dirvožemiu plintantys virusai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20090908_194007-85939.
Full textAbstract:
SANTRAUKA Potato mop-top virus, priklausantis Pomovirus genčiai ir Tobacco rattle virus, priklausantis Tobravirus genčiai – tai dirvožemiu plintantys virusai. Tai patogenai, kurie plačiai paplitę pasaulyje. Pastaruoju metu vis labiau susidomėta šiais virusais, mat jie sukelia daug žalos daugeliui augalų, tame tarpe ir labai svarbių kultūrinių augalų. Su šiais patogenais kovoti yra labai sudėtinga, taigi iškyla labai rimta problema, kurią bandoma išspręsti. Todėl šiame darbe ir buvo siekiama susipažinti su šiais virusais, jų pernešėjais bei padaryti pirmuosius žingsnius, ieškant būdus kovai su šais patogenais. PMTV – tai patogenas, kuriam nebūdingas gausus šeimininkų ratas. Jis infekuoja tik nedaugelį augalų rūšių. Tai viena iš savybių, kuria skiriasi nuo TRV. Pastarasis priešingai, pasižymi didele augalų-šeimininkų gausa. Šie virusai labai panašūs tuom, kad daugelyje augalų jie sukelia panašius simptomus bei pažeidimus. Net indikatoriniuose augaluose jų sukeltos žaizdos yra labai panašios. Taigi, susiduriama su problema, mat identifikuoti juos vizualiai yra labai sudėtinga. Tik N. benthamiana indikatorinis augalas gali padėti atskirti šiuos virusus: PMTV jame sukelia sisteminę reakciją, sisteminė mozaika išplinta po visą augalą, o TRV sukelia tik vietines žaizdas. Šiame baigiamajame darbe buvo siekiama identifikuoti PMTV bei TRV molekuliniais metodais. Identifikacijoje buvo pritaikytas imunofermentinis metodas – ELISA. Buvo nustatyta, kad šis metodas labiau tinka... [toliau žr. visą tekstą]<br>SUMMARY Potato mop-top virus (genus Pomovirus) and Tobacco rattle virus (genus Tobravirus) – soil born viruses. These pathogenes are distributed worldwide and can significantly reduce the quality and yield of potato and other horticultural plants. So in recent years more and more people are interesting in these viruses. These viruses are responsible for economic losses in potato crops. To control the spread of viruses is vary difficult, so nowadays it is a serious problem, which everybody wants to solve it. Virus control depends on vector management, so the main purpose of this article was to know more about these viruses and thier vectors and to do first steps to finding ways of viruses’ suitable control measures. PMTV has narrow range of hosts. On the contrary TRV has a very wide natural host range. So it is one of the differences from these soil borne viruses. However diagnosis is further complicated by the fact that TRV and PMTV are very similar viruses, even they can cause similar symptoms to indicator plants. So to diagnose reliable these viruses by visual symptoms are very difficult. Just in indicator plant N. benthamiana these soil borne viruses cause different symptoms: PMTV cause sistemical reaction, sistemical mosaic spreads in whole plant and TRV cause local lessions. PMTV and TRV were identificated with different molecular methods. These viruses were detected by enzyme-linked immunosorbent assay. DAS-ELISA was shown to be more sensetive and reliable method for... [to full text]
40
Wasswa, Peter. "Sweet potato viruses in Uganda : identification of a new virus, a mild strain of an old virus and reversion." Thesis, University of Greenwich, 2012. http://gala.gre.ac.uk/9091/.
Full textAbstract:
In 2009, a sweet potato begomovirus (sweepovirus) was detected for the first time in Uganda. An isolate was sequenced, providing the first full sequence of a sweepovirus from mainland Africa which differed from other sweepoviruses by at least 13%, discriminating this isolate as a new species, ‘Sweet potato leaf curl Uganda virus’ (SPLCUV). SPLCUV was quite common in cultivars (cvs) Ejumula, New Kawogo and 318L having uneven distribution in infected plants and reversion to healthy occurred, especially in cv New Kawogo. SPLCUV was observed not to be synergised by Sweet potato chlorotic stunt virus (SPCSV), apparently making it the first report of a sweet potato virus not synergised by SPCSV. Besides SPLCUV, a ‘mild’ SPCSV strain that induced purpling symptoms and 50% yield reduction similar to wild type SPCSV when infecting alone was identified from Busia district, Uganda. ‘Mild’ SPCSV was never observed to be co-infected with Sweet potato feathery mottle virus (SPFMV) in farmers’ fields. Experimentally, ‘mild’ SPCSV induced mild symptoms in Ipomoea setosa and sweet potato plants and SPFMV titre was greater in co-infections of SPFMV and wild type SPCSV than in co-infections of SPFMV and ‘mild’ SPCSV. Both RNase3 (accession No. HE575406) and p22 (accession No. HE575409) genes on RNA1 of ‘mild’ SPCSV compared closely to those reported previously. Instead, RNA1 region appears to be expressed less in the ‘mild’ SPCSV infection than in the wild type SPCSV infection though RNA2 continues to be more expressed in the ‘mild’ SPCSV infection than in the wild type SPCSV infection. Recovery from SPVD symptoms and reversion from SPFMV were observed in cv Kampala White co-infected with ‘mild’ SPCSV and SPFMV. Reversion from SPFMV single infections occured in several landraces with higher rates observed in shoots of resistant than susceptible cultivars. Overall, cv NASPOT 11 was the fastest to revert while cv Beauregard was the slowest.
41
Moore, Mary Linda. "The molecular relationship of potato virus V with other members of the potvirus group." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334485.
Full text
42
Carrión, Herrera Cinthya María. "“Detección temprana del Potato Yellow Vein Virus en cultivos de Solanum tuberosum L. mediante la teledetección”." Bachelor's thesis, Universidad Ricardo Palma, 2017. http://cybertesis.urp.edu.pe/handle/urp/871.
Full textAbstract:
El Potato yellow vein virus (PYVV) es un Crinivirus perteneciente a la Familia Closteroviridae, el cual reduce la producción total de papa en América del Sur hasta un 50%. La detección visual de los cultivos es una práctica habitual, pero la enfermedad generalmente se detecta después de que se ha producido un daño significativo a los tejidos fotosintéticos.
A través de técnicas de teledetección se puede evaluar el estado nutricional y fitosanitario de las plantas, detectando incidencias de plagas y enfermedades e inferir posibles carencias nutricionales. Con el objetivo de detectar la infección de PYVV en cultivos de papa antes de la aparición de los síntomas visuales se empleó la técnica de teledetección, mediante el uso del espectroradiómetro.
Se llevaron a cabo 5 experimentos, empleando 5 variedades de papa: Única, Clon W.A., Canchan INIA, Amarillis y Costanera. La infección con PYVV fue inducida mediante injerto lateral.
Se tomaron 3 mediciones espectroradiométricas por cada planta 2 veces por semana durante todo el periodo de observación y se realizó una evaluación visual continua de los síntomas. Asimismo, se confirmó la presencia del virus PYVV mediante RT-PCR. Finalmente, se evaluó el rendimiento de las 5 variedades y se identificó la variedad más susceptible al virus.
Se pudo hacer un diagnóstico precoz de la infección por PYVV en las 5 variedades de papa. La variedad Canchan INIA se detectó entre 8 y 14 días antes de la aparición de los síntomas visuales, Única entre 7 y 18 días, Costanera entre 12 y 17 días, Amarillis entre 6 y 12 días, y finalmente Clon W.A. se pudo detectar entre 2 y 11 días antes de la aparición de los síntomas.
La variedad Canchan INIA fue la variedad más susceptible al virus, ya que presentó el mayor porcentaje de reducción en el rendimiento, con un 36.63%, seguido de Costanera y Amarillis con un 28.57% y 28.31%, respectivamente. Clon W.A. fue la variedad menos afectada en cuando a la reducción en el rendimiento, con un 6.67%.Potato yellow vein virus (PYVV) is a Crinivirus belonging to the Closteroviridae Family, which reduces the total potato production in South America up to 50%. Visual detection of cultures is a common practice, but the disease is usually detected after significant damage to photosynthetic tissues has occurred. Through remote sensing techniques, it is possible to evaluate the nutritional and phytosanitary status of plants, detecting pest and disease incidences and inferring possible nutritional deficiencies. In order to detect PYVV infection in potato cultures before the appearance of visual symptoms, the technique of remote sensing was used, using the spectroradiometer.
Five experiments were carried out, using 5 varieties of potato: Única, Clon W.A., Canchan INIA, Amarillis and Costanera. Infection with PYVV was induced by lateral grafting.
Three spectroradiometric measurements were taken per plant 2 times per week throughout the observation period and a continuous visual evaluation of the symptoms was performed. Also, the presence of the PYVV virus was confirmed by RT-PCR. Finally, the yield of the 5 varieties was evaluated and the variety more susceptible to the virus was identified.
An early diagnosis of PYVV infection could be made in all 5 potato varieties. Canchan INIA variety was detected between 8 and 14 days before the appearance of visual symptoms, Unica between 7 and 18 days, Costanera between 12 and 17 days, Amarillis between 6 and 12 days, and finally Clon W.A. could be detected between 2 and 11 days before the onset of symptoms.
Canchan INIA variety was the most susceptible to the virus, as it presented the highest percentage reduction in yield, with 36.63%, followed by Costanera and Amarillis with 28.57% and 28.31%, respectively. Clon W.A. was the least affected variety when compared to the reduction in yield, with 6.67%.
43
Rahman, Sanzida. "Differentiating PVY Infection from Nitrogen Deficiency in Potato Using Spectral Reflectance." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/31695.
Full textAbstract:
Potato Virus Y (PVY) infection and nitrogen (N) deficiency cause similar symptoms (chlorosis and stunting) on potato foliage. While conventional methods, including ELISA and petiole testing, require destructive sampling and a longer time to diagnose, spectral analysis can be non-destructive, rapid and efficient. Spectral reflectance for potato cultivars representing three market types, chip processing, red-skinned fresh, and fresh and processing russets, were assessed in separate greenhouse trials in response to three N rates (90, 200, and 290 kg/ha) and two PVYN:O infection levels (clean and infected) at 4, 6, and 8 weeks after inoculation (WAI). Normalized Difference Vegetation Index (NDVI) was able to differentiate clean and PVYN:O infected samples of red-skinned and chip processing cultivars, at 4 and 8 WAI, respectively. Overall, cultivars differed in their spectral responses, indicating the importance of studying cultivar-specific spectral responses against PVY infection in future.
44
Gammelgård, Elin. "Interactions of potato virus A with host plants : recombination, gene silencing and non-hypersensitive resistance /." Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007111.pdf.
Full text
45
Anderson, Shirley Victoria. "The nucleotide sequence and genomic organization of the potato mop-top virus RNA-2 molecule." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334531.
Full text
46
Untiveros, Lázaro Milton. "Estudio de la Variabilidad Genética del Sweet potato feathery mottle virus (SPFMV) y virus relacionados existentes en camote [Ipomea batatas (L.)]." Master's thesis, Universidad Nacional Mayor de San Marcos, 2010. https://hdl.handle.net/20.500.12672/1346.
Full textAbstract:
En el Perú son varios los potyvirus que se encuentran infectando el camote (Ipomoea batatas), siendo el mas común el Sweet potato feathery mottle(SPFMV). Sin embargo, actualmente no existen datos de secuencia nucleotídica par estos virus. En el presente estudio, se determinaron y analizaron los datos de la secuencia nucleotídica de la región 3’ terminal (~1800 pb) de 17 aislamientos de potyvirus colectados de campos que se encuentran en las seis principales zonas de cultivo de camote en el Perú. Los resultados de la comparación de secuencias y análisis filogenéticos mostraron que tres de las cuatro cepas que son reconocidas dentro del SPFMV, se encuentran en el Perú, incluyendo la cepa Este de Africa. Del mismo modo, se encontraron aislamientos pertenecientes de otros dos potyvirus denominados sweet potato virus G(SPVG) y sweet potato virus 2 (SPV2). Análisis posteriores revelaron que SPFMV, SPVG y SPV2 son virus relacionados y forman una línea filogenética
dentro del genero Potyvirus que tienen como hospederos a plantas del genero Ipomoea. El estudio también reporta la ocurrencia de eventos de recombinación entre aislamientos de diferentes cepas de SPFMV.<br>Several potyviruses are found infecting sweet potato (Ipomoea batatas) in Peru, of which sweet potato feathery mottle virus (SPFMV, genus Potyvirus) is the most common. However, sequence data for these viruses are not available from Peru. In this study, the 3’-terminal ~1,800 nucleotide sequences of 17 potyvirus samples collected from the six main sweet potato-producing areas of Peru were determined and analyzed. Results of sequence comparisons and phylogenetic analysis showed that three of the four recognized SPFMV strain groups, including the East African strain, are established in Peru as well as two other potyviruses: sweet potato virus G (SPVG) and sweet potato virus 2 (SPV2). The analysis further revealed that SPFMV, SPVG and SPV2 are related and form an Ipomoea-specific phylogenetic lineage within the genus Potyvirus and identified for the first time recombination events between viruses from different strain groups of SPFMV.<br>Tesis
47
Bendahmane, Abdelhafid. "Analysis of a gene-for-gene interaction associated with Rx-mediated resistance to potato virus X." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389350.
Full text
48
Wambugu, Florence Muringi. "In vitro and epidemiological studies of sweet potato (Ipomoea batatas) (L.) Lam. virus diseases in Kenya." Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303296.
Full text
49
Fourie, Michelle Louise. "The potential of wheat, maize, lucerne, and soybean as plant borders to reduce aphid-transmitted virus incidence in seed potatoes." Pretoria : [s. n.], 2008. http://upetd.up.ac.za/thesis/available/etd-09042009-172734/.
Full text
50
Jaag, Hannah Miriam. "Translationsmechanismen in Pflanzen am Modellsystem potato leafroll virus (PLRV) interner Ribosomeneintritt steuert die Synthese des Replikations-Proteins RAPI /." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963638769.
Full text