Dissertations / Theses: 'Host resistance in plants'

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Wilson, F. D., and H. M. Flint. "Host Plant Resistance." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/203923.

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Wilson, F. D., and H. M. Flint. "Host Plant Resistance." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219754.

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The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.
Cotton breeding stocks were evaluated for resistance to pink bollworm. Resistance is being transferred into improved agronomic stocks.

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Cameron, Duncan Drummond. "A role for differential host resistance to the hemiparasitic angiosperm, Rhinanthus minor L. in determining the structure of host plant communities?" Thesis, University of Aberdeen, 2004. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238495.

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This study describes the effect of the root hemi-parasitic angiosperm Rhinanthus minor on the structure of the communities in which it lives and seeks to elucidate a mechanism through which the parasite acts to effect these changes in the community. Field manipulations reveal that R. minor suppressed the growth of grasses and legumes in a newly sown meadow whilst promoting the forbs within one growing season. In contrast the removal of R. minor from mature meadow plots did not influence their composition. After an additional growing season the parasite did not further influence the composition of the new meadows but removal did begin to benefit the biomass of mature plots. In isolation the parasite caused most damage to grasses whilst leaving legumes and forbs undamaged. Moreover, the parasite performed worst in terms of growth and photosynthesis when attached to the forbs. Consequently the parasite was able to moderate intra-specific competition between grasses and forbs. I thus hypothesised that forbs were able to prevent the parasite form abstracting resources where as grasses could not. Tracer experiments using isotopically e5N) labelled potassium nitrate confirmed this hypothesis showing that more of the resources taken up by the host were stolen by the parasite from grasses than from forbs. There was much variability in the translocation of resources from the legume studied. The reasons underlying the differential uptake of resources were highlighted using histological studies which showed that all of the forbs possessed successful resistance mechanisms to the parasite whilst no successful resistance was observed in the grasses or legumes. Two different resistance mechanisms were observed in the forbs; hypersensitive cell-death at the host-parasite interface and host lignification. I therefore propose that differential host resistance may underlie this parasite's community level effects as forbs possess a resistance capacity that other potential hosts do not.

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Soriano, Imelda Rizalina. "Novel inducible phytochemical defences against plant parasitic nematodes /." Title page, table of contents and summary only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phs7141.pdf.

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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.

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Madumadu, Glynn George. "Inheritance of resistance to Corynebacterium michiganense (E.F. Sm.) H.L. Jens in tomato (Lycopersicon esculentum) and effect of host nutrition (N and CA) on resistance /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487259580261617.

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Beswetherick, John T. "An ultrastructural study of host and non-host resistance reactions in plant cells." Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292658.

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Chigurupati, Pavan Chandra. "Role of SABP2 in Tobacco Non-Host Resistance." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etd/1393.

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Plant innate immunity is activated upon pathogen attack by recognizing their avirulent (avr) genes by Resistant (R) genes leading to R-gene resistance or host resistance. Another form of innate immunity is non-host resistance that is exhibited by a given plant species to most strains of a microbial species. R-gene resistance activates salicylic acid (SA) that is synthesized from methyl salicylic acid (MeSA) by Salicylic Acid Binding Protein 2 (SABP2). It was hypothesized that SABP2 plays the similar role in non-host resistance also. Growth experiments and non-host related gene analysis experiments were conducted on tobacco plants using P.s tabaci and P.s. phaseolicola that are host and non-host pathogens on tobacco respectively. Tobacco control plant C3 that expresses SABP2 and 1-2 that is RNAi silenced in SABP2 expression were used in this study. Results suggest that SABP2 may not have any significant role in tobacco non-host resistance.

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Krenz, Jennifer E. "Specificity of quantitatively expressed host resistance to Mycosphaerella graminicola /." Connect to this title online, 2007. http://hdl.handle.net/1957/3813.

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Vigier, Bernard. "Host plant resistance and epidemiology of Fusarium ear rot in maize." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ28380.pdf.

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Al-Kherb, S. M. "The inheritance of host-specific pathogenicity in Phytophthora infestans." Thesis, Bangor University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380792.

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Hayward, J. M. "Changes in host gene expression associated with induced resistance to plant viruses." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603896.

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Salicylic acid (SA) induces systemic acquired resistance (SAR) to a wide range of pathogenic microbes. The defensive signal transduction pathway branches downstream of SA in tobacco (Nicotiana tabacum) and Arabidopsis thaliana. One branch leads to resistance to fungi and bacteria. The other, antimycin A (AA)-induced, branch, the virus-specific signalling pathway (VSSP), leads to resistance to viruses. In this study I showed, using cDNA-AFLP, that certain genes induced or repressed in tobacco leaf tissue expressing SAR were also induced or repressed by the VSSP (induced using AA). The regulation of three of these genes was verified using RT-PCR. A preliminary investigation of the temporal and tissue-specific regulation one of these genes (B2) was carried out. B2 was constitutively expressed most strongly in the leaf lamina, less strongly in the vein, weakly in the stem and not at all in the roots of healthy tobacco plants. Following induction of SAR or the VSSP B2 transcript was found to increase steadily for up to 24 hours. B2 accumulation increased from the basal level only in the leaf lamina. B2 transcript was induced in both the pathogen inoculated and the distant (non-inoculated) leaves of tobacco resisting Tobacco mosaic virus (TMV)-infection. These experiments strengthened the correlation between B2 induction and resistance to viruses. Post-transcriptional gene silencing (PTGS) is another inducible anti-viral defence mechanism in plants. PTGS requires the activity of an RNA-dependent RNA polymerase (RdRp). The recent discovery of a SA-regulated, plant-encoded RdRp (NtRdRp1) in tobacco suggested that there is a link between PTGS and SA-dependent resistance. I found that although NtRdRp1 is indeed induced by SA, it is not induced by AA, and thus this gene is unlikely to be regulated by the VSSP. It has been proposed that the VSSP requires the activity of alternative oxidase (AOX), the terminal oxidase of the plant mitochondrial alternative respiratory pathway (AP). I tested this theory in transgenic tobacco lines with increased or decreased AP capacity, relative to untransformed tobacco. I found that TMV accumulation in inoculated tissue was similar in untreated transformed and untransformed plants.

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Kazemi, M. H. "Identification and mechanisms of host plant resistance to cereal aphids in wheat." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384142.

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Rufener, George Keith. "A genetic and biochemical study of the antibiosis mechanism of host-plant resistance in soybeans to the Mexican bean beetle /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487335992902504.

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Ganguly, Subhendu. "Possible tritrophic consequences of high levels of host plant resistance (as in transgenic resistance) to aphids in Brassicaceae." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267425.

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Mekala, Diwakar Karthik. "Screening upland cotton for resistance to cotton fleahopper (Heteroptera: Miridae)." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/1071.

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Cotton (Gossypium hirsutum L.) crop maturity is delayed by cotton fleahopper (Pseudatomoscelis seriatus Reuter) (fleahopper) feeding on early-season fruit forms which increases vulnerability to late-season pests such as Helicoverpa zea (Boddie) and Heliothis virescens (Fabricius). The objectives of this research were to evaluate methods of screening for resistance to fleahopper and to screen selected genotypes. Six fleahoppers were caged on plants in the insectary for 72 h. Numbers of live fleahoppers and percent square damage were determined 48 h following the removal of fleahoppers. Fleahopper numbers and percent square set were determined on randomly selected plants of 16 genotypes when grown under field conditions in 2002 and 2003. Across multiple sampling dates, the number of fleahoppers per plant was higher (p=0.05) in G. arboreum and Pilose (G. hirsutum), but no consistent differences were observed among the remaining 15 genotypes which represented several germplasm pools across the United States. Field and no-choice feeding tests suggested that Pilose, Lankart 142, Suregrow 747, and Stoneville 474 were more resistant hairy-leaf genotypes and not different (p=0.05) in resistance than the smooth-leaf genotypes, Deltapine 50 and TAM 96WD-69s. Pin-head, match-head, and one-third grown squares were removed from plants and placed on agar in petri-plates. Four fleahoppers were released per plate and allowed to feed for 48 h. Fleahopper damage, brown areas along the anthers and/or brown and shrunken pollen sacs was most evident in pin-head sized squares.

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17

Diedrick, Keith A. "Reduced insecticide rates and host plant resistance for managing Potato Leafhopper in Alfalfa." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1413291380.

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Luczynski, Anna. "Chemical and morphological factors of resistance against the twospotted spider mite (Tetranychus urticae Koch) in beach strawberry Fragaria chiloensis (L.) Duchesne." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27981.

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Host-plant resistance is an important component of integrated pest management. Host resistance to phytophagous insects and mites based on chemical and morphological characteristics has been identified in various agronomic crops. The present study was undertaken to examine how variation in selected morphological and chemical characteristics of beach strawberry Fragaria chiloensis (L.) Duchesne affects population parameters of the twospotted spider mite Tetranychus urticae Koch. The results from this study show that clones of F. chiloensis and the cultivar "Totem" vary in suitability for the twospotted spider mite. Selected clones of F. chiloensis and the cultivar "Totem" differed also in the following foliar characteristics: densities of glandular and nonglandular trichomes and concentrations of total and catechol-based phenolics. In contrast, qualitative analysis of phenolic compounds, determined via HPLC, revealed a close similarity between F. chiloensis and F. x ananassa (cultivated strawberry) and among selected clones of F. chiloensis. Mite oviposition was negatively correlated with densities of glandular and nonglandular trichomes and concentrations of total foliar phenolics. In spite of these significant relationships, mite oviposition was best predicted by a combination of interacting plant characteristics rather than by any individual characteristic. Entrapment by sticky exudates from glandular trichomes appears to explain the negative relationship between mite survival and density of glandular trichomes. Spider mite development was negatively related to concentrations of foliar phenolics; twospotted spider mite development is delayed on leaves with high concentrations of phenolics. The correlation between mite development and foliar phenolics was greater when catechol-based phenolics were used.
Land and Food Systems, Faculty of
Graduate

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19

Schwanck, André. "Identifying epidemiological predictors for quantitative host plant resistance : application to the sunflower-phoma pathosystem." Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/15954/1/Schwanck.pdf.

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Phoma black stem (BS) is caused by the fungus Leptosphaeria lindquistii, and is an important disease in France. The study presented in this dissertation provides useful information on BS epidemiology and sunflower quantitative resistance against the disease. Experiments were conducted on plants grown in small plots (field), adult plants (greenhouse), and seedlings (growth chamber) in order to (1) characterize the spatiotemporal dynamics of BS, (2) identify morphological traits affecting BS through disease escape processes and utilizing a standardised disease assessment procedure, and (3) identify predictors of quantitative resistance to BS. This study suggests that (1) BS is primarily associated to monocyclic epidemics in south west France, (2) low BS levels are associated with sunflower plants characterized by a large number of green leaves and large height, and (3) predictors of quantitative resistance to BS can be experimentally identified.

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20

Griffitts, Amanda Aline. "Characterization of Host Plant Defense Responses to Parasitization by Orobanche aegyptiaca." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/42763.

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Orobanche (spp.) are parasitic plants that attack the roots of many important crops. O. aegyptiaca penetrates the host root (aided by digestive enzymes) and forms connections to the host vascular tissue, from which it will withdraw all of its water and nutrient requirements. In order to control this weed, it is important to understand the relationship between the host and the parasite. To investigate how parasitism effects host defense pathways, we are studying the patterns of expression of host genes known to be involved in various aspects of plant defense responses. With respect to local defense responses, two genes of the isoprenoid pathway were studied, one of which is expressed in wounded tissue (hmg1), and another that is induced in response to wounding yet repressed in response to pathogen elicitors (squalene synthase). Genes analyzed that are associated with systemic defense include PR-1, PR-2, and PR-5, all of which are induced in response to pathogen attack as part of the systemic acquired resistance (SAR) response. Plant gene expression was studied using transgenic tomato plants containing hmg1-GUS fusions, and northern hybridization analysis of tobacco and Arabidopsis roots using gene-specific probes. Results indicated that expression of hmg1 is induced, PR-2 and squalene synthase are repressed, and PR-1a, PR-1, and PR-5 are not affected in tissue parasitized by O. aegyptiaca. Together, these results indicate a complex response to the parasite. Whereas hmg1 induction is consistent with O. aegyptiaca inflicting a simple wound-like injury, the repression of squalene synthase is consistent with plant recognition of a pathogen attack. In contrast, the failure of Orobanche to induce SAR- related PR-1 in tobacco and PR-1, PR-2, or PR-5 in Arabidopsis indicates an ability to avoid or perhaps inhibit some defense-related pathways. By comparing the regulation of these defense genes in response to O. aegyptiaca attack, we are able to gain a greater understanding of the host plant response to parasitization and explore potential gene candidates for future engineering strategies to create Orobanche resistant crops.
Master of Science

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21

Gangadharan, Anju. "Characterization of defense pathways and genes involved in host-pathovar level resistance using Arabidopsis-Pseudomonas system." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387815106.

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22

Mgonja, Emmanuel Mohamed. "Molecular Analysis of Host Resistance and Pathogenicity of Rice Blast in East Africa." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471537840.

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O'Connell, Dean Michael, and n/a. "Plant-arthropod interactions : domatia and mites in the genus Coprosma (Rubiaceae)." University of Otago. Department of Botany, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090807.160026.

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Plant-based defence mutualisms involve aspects of plant morphology that influence the performance of plant parasites, their natural enemies and trophic interactions. Leaf domatia, small indentations on the underside of leaves, can be structurally complex, and are often inhabited by potentially beneficial mites and other arthropods. Plant morphological traits such as domatia that enhance mutualistic relationships may result in increased plant growth rates, and reproductive success. New Zealand supports ~60 plant species that have domatia, the most speciose genus being Coprosma. The aim of this thesis was to examine factors that affect the production of leaf domatia and their relationship with foliar mite assemblages. The three main objectives of this thesis are: First, to investigate the production of foliar domatia and their susceptibility to limited resources, particularly to carbon availability. Second, to test if domatia are inducible structures during leaf ontogeny in the presence of foliar mites and/or fungi. Finally, to explore the effect of domatia availability on foliar mite assemblages on leaves with and without resident mites. This thesis tested the stated objectives using C. lucida, C. ciliata, C. foetidissima and C. rotundifolia, with a combination of field investigations and controlled manipulative experiments. The cost of domatia production was investigated using two field surveys and two controlled experiments. Under natural conditions the relationship between leaf morphology and domatia were measured in situ and across an altitudinal gradient. The experimental manipulations used carbon and nutrient stress, induced by temperature, light and fertilizer application. The second objective was experimentally tested under field conditions by manipulating foliar mites and fungal densities on C. rotundifolia. The third objective was investigated by manipulating domatia availability on C. lucida shrubs across three different vegetation types. Under field conditions, the number of domatia per leaf was associated with leaf morphology in C. lucida and C. foetidissima, but not C. rotundifolia. Foliar carbon showed a positive, but weak association with domatia production in C. foetidissima and C. ciliata. Altitudinal induced-carbon stress on domatia production was ambiguous. Domatia production in C. foetidissima was positively associated to altitude in field survey (1), and negatively associated in the second survey, with no correlation found between carbon and altitude. Experimental C. rotundifolia shrubs held under elevated night-time temperatures showed a 2.5 fold increase in respiration, a 34% to 91% decrease in daily carbon gain, and 38% decrease in domatia per leaf mass. Domatia production showed no significant differences under nutrient stress. The results showed little evidence to support a role for induction of domatia. Domatia production in new leaves was similar across all experimental treatments. Diverse vegetation types supported 60% higher mite species. Leaves with domatia supported ~22 to 66% higher mite densities, greater colonisation success and more diverse mite assemblages, than those without domatia. In the pastoral vegetation, the absence of predatory mites on experimental shrubs resulted in no differences in fungivorous mite densities regardless of domatia availability. Plant investment in foliar domatia appears associated with the number of available sites on the leaf under field conditions. The role of carbon availability during leaf ontogeny suggests a complex and highly variable association with domatia production. Domatia are constitutive defence structures that influence mite assemblages, mediating both beneficial and antagonistic relationships. This thesis concludes that domatia are in part, carbon-based non-inducible structures that influence mite assemblages, plant-mite and mite-mite interactions, and increase the probability of successful colonisation.

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Viswanathan, Poornima. "Effect of previous feeding on antibiosis levels of soybeans." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/9181.

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Master of Science
Department of Entomology
John C. Reese
The soybean aphid, Aphis glycines is documented to have arrived in North America in mid 2000 and has ever since established itself as a formidable pest of soybeans, with the capacity to cause immense crop losses. This formidable pest with its complex life cycle and habits represents a current threat to soybean production. Host plant resistance is a promising avenue that can offer considerable control over the soybean aphid problem. Antibiosis being the most effective host plant resistance category, this study was aimed at attempting to understand the effects of induction on the antibiosis levels of soybeans. In the first set of experiments, different soybean genotypes and two soybean aphid biotypes were tested to comprehend if and how the genotypes and biotypes affected the survival and reproduction of the aphid. The experiments revealed mixed results that can be attributed to the genotypes tested and the biotypes used. While some genotypes showed no significant changes due to previous infestation, K1621 suggested signs of induced resistance to biotype 1 and PI567301B showed induced resistance to biotype 2, while K1639 pointed towards induced susceptibility to biotype 2. A follow up feeding behavior study with Electrical Penetration Graph (EPG) technique was carried out on PI567301B to elucidate if the induced resistance was tissue-specific, which could affect the feeding behavior of the aphid (biotype 2); but the results showed no appreciable differences in the feeding behavior of the aphids on clean vs. infested plants. Induced response studies shed light on how plants respond to herbivory and help us identify how changes in plant physiology affect the various herbivores that visit it for food and shelter. This knowledge can thus be applied to the development of superior varieties of crops that can defend themselves better against recurring infestations.

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Méndez, Espinoza Claudia. "White spruce resistance against the spruce budworm : genetic control and insect-host interaction." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/33970.

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Picea glauca (Moench) Voss (l’épinette blanche) est l’un des principaux hôtes de la tordeuse des bourgeons de l’épinette (TBE), le défoliateur épidémique le plus dommageable de l’est du Canada qui est à l’origine de la mortalité d’arbres et de pertes économiques d’envergure considérables. Un mécanisme constitutif de résistance contre la TBE a récemment été découvert. Dans la présente thèse, nous avons étudié ce mécanisme basé sur l’accumulation foliaire du picéol et du pungénol, deux acétophénones découlant de la surexpression du gène Pgglu-1. Ces trois facteurs sont désignés comme étant des «biomarqueurs de résistance». Nous avons aussi étudié la picéine, un acétophénone glycosilé qui est le précurseur du picéol, et l’ensemble des quatre facteurssont désignés «biomarqueurs de défense». La première partie de la thèse présente une approche de génétique quantitative s’appuyant sur l’analyse de 874 arbres représentant 33 familles et 71 lignées clonales répartis dans sept emplacements de l’est du Canada. Nos objectifs étaient : i) de déterminer le contrôle génétique des biomarqueurs de défense, ii) d’estimer les corrélations génétiques et phénotypiques entre les quatre traits de défense, iii) d’évaluer la présence de compromis entre les biomarqueurs de défense et la croissance primaire. Nous avons conclu que l’héritabilité au sens strict du picéol, du pungénol et de l’expression du gène Pgglu-1 était modérée (0,55, 0,50 et 0,58 respectivement), et obtenu des estimés un peu plus élevées pour l’héritabilité au sens large du picéol et du pungénol (0,66 et 0,60 respectivement), ce qui indique que ces traits de résistance sont soumis à un contrôle génétique additif. Les traits de résistance et la croissance montrent des corrélations génétiques positives (de 0,14 à 0,30), ce qui suggère que le mécanisme de résistance n’entraine pas un effet négatif sur la croissance de l’épinette blanche. Dans la deuxième partie de la thèse, nous avons étudié l’interaction insecte-hôte en menant des essais d’élevage d’insectes sur différents clones d’épinettes blanches. Nos objectifs étaient iv) de caractériser la variation développementale des acétophénones de défense, v) d’évaluer l’influence du stade phénologique de l’hôte sur le niveau de résistance indiqué par la performance biologique de la TBE et vi) de déterminer si les traits de résistance sont inductibles. Nous concluons que la variation des acétophénones dépend du phénotype de résistance de l’arbre, et que l’efficacité des traits de résistance dépend du synchronisme entre le Piceaglauca et l’alimentation des insectes. Finalement, nous avons démontré que ce mécanisme de résistance peut être inductible.
Picea glauca (Moench) Voss (white spruce) is one of the main hosts of the spruce budworm (SBW), anepidemic defoliator that is the most damaging in forests of eastern North America causing tree mortality and large economic losses. A constitutive resistance mechanism against the SBW was recently discovered. In this thesis, we studied this mechanism based on the foliar accumulation of aglycon acetophenones ̶piceol and pungenol ̶resulting from the expression of the Pgglu-1gene; and we refer to them as resistance biomarkers. Picein, the glycoside precursor of piceol was also investigated and we refer to all four traits togetheras defense biomarkers. The first part of this thesis presents a quantitative genetic study, which analysed 874 trees representing 33 full-sib families and 71 clonal lines from seven field locations in Eastern Canada. The goals were to i) determine the genetic control of the defense biomarkers, ii) estimate the genetic and phenotypic correlations among the four defensive traits and growth, and iii) evaluate the occurrence of trade-offs between the defense biomarkers and primary growth. Narrowsense heritability of piceol, pungenol and Pgglu-1 gene expression was moderate (0.55, 0.50 and 0.58, respectively). Slightly higher broad sense heritability estimates were obtained for acetophenones (0.66 and 0.60 respectively), indicating that additive genetic effects playa major role in these resistance biomarkers. Positive genetic correlations were found between the resistance traits and growth (from 0.14 to 0.30), suggesting that the resistance mechanism does not compromise growth in white spruce. In the second partof the thesis, we studied the insect-host interaction by use of insect rearing trials in severalwhite spruce clones. Our objectives were to iv) characterize the developmental and phenological variation of the defense acetophenones, v) evaluate the impact of the matched and delayed host phenology windows on the biological performance of the SBW, and vi) assess the inducibility potential of the resistance traits. Weshow that there are considerable variations in the acetophenone accumulation profiles between individual trees supporting their classification as Resistant (R) and Non-Resistant (NR); that the efficiency of the resistance traits is influenced by the synchronization between the P. glauca phenology and the insect feeding. Finally, we show that the resistance mechanism can be inducible.

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Aucique, Pérez Carlos Eduardo. "Wheat resistance to blast using a non-host selective toxin and host metabolic reprogramming through a successful infection by Pyricularia oryzae." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/21193.

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A brusone, causada por Pyricularia oryzae, é considerada uma doença economicamente importante para trigo na América do Sul. Uma das estratégias de manejo para minimizar as perdas causadas por essa doença é o uso de cultivares resistentes. Alternativamente, pode-se utilizar indutores de resistência para aumentar o nível basal de resistência do trigo à brusone. O presente estudo teve como objetivos: i) determinar as alterações fisiológicas e bioquímicas em plantas de trigo pulverizadas com uma concentração não fitotóxica do ácido α-picolinico (AP), o qual é uma toxina não seletiva produzida por P. oryzae e ii) verificar a manipulação metabólica exercido por P. oryzae quando infectando cultivares de trigo com diferentes níveis de resistência basal à brusone. Nas folhas de trigo pulverizadas com uma concentração não fitotóxica de AP (0.1 mg mL -1 ), os sintomas da brusone desenvolveram menos em associação com um melhor desempenho fotossintético, melhoria do metabolismo antioxidante e redução nas concentrações de H 2 O 2 , O 2 ●- e MDA. As cultivares BR-18 e EMBRAPA- 16 foram mais resistentes à brusone do que a cultivar BRS-Guamirim. O desempenho fotossintético das plantas infectadas foi alterado devido a limitações de natureza difusiva e bioquímica para uma eficiente fixação do CO 2 . Durante a fase assintomática da infecção por P. oryzae, mudanças drásticas no metabolismo de carboidratos e nos níveis de aminoácidos, compostos intermediários do ciclo de Krebs e poliaminas ocorreram nas plantas das três cultivares sugerindo, assim, uma manipulação metabólica exercida por P. oryzae. No entanto, um metabolismo antioxidativo mais eficiente foi importante para neutralizar os efeitos deletérios da infecção por P. oryzae em associação com maiores atividades da fenilalanina amônia liase e polifenoloxidase e maiores concentrações de compostos fenólicos e lignina. Com base nesses resultados e possível concluir que a concentração não fitotóxica de AP foi capaz de potencializar a defesa das plantas de trigo e reduzir a severidade da brusone. A infecção do trigo por P. oryzae ocasionou distúrbios no metabolismo primário das plantas e alguns deles foram semelhantes entre as cultivares independentemente do nível basal de resistência delas.
Blast, caused by Pyricularia oryzae, has become an economically important disease in wheat in South America. One of the management strategies for minimizing the losses caused by blast includes the use of resistant cultivars. Alternatively, the use of inducers of resistance showed the potentiation to increase wheat resistance to blast. This study aimed: i) to determine the physiological and biochemical alterations in wheat plants sprayed with a non-phytotoxic concentration of α-picolinic acid (PA), which is a non-host selective toxin produced by P. oryzae and ii) to establish the degree of metabolic manipulation exerted during the infection by P. oryzae on plants from cultivars with different levels of basal resistance to blast. The spray of leaves of plants with a non-phytotoxic concentration of PA (0.1 mg mL -1 ) resulted in less blast symptoms in association with a better photosynthetic performance, an improvement on the antioxidant metabolism and reduced concentrations of H 2 O 2 , O 2 ●- and malondialdehyde. The cultivars BR-18 and EMBRAPA-16 were more resistant to blast in comparison to cultivar BRS-Guamirim. The photosynthetic performance of the infected plants was altered due to diffusional and biochemical limitations for CO 2 fixation. During the asymptomatic phase of P. oryzae infection, drastic changes in the carbohydrates metabolism and on the levels of amino acids, intermediates compounds of Krebs cycle and polyamines occurred on plants from the three cultivars suggesting a metabolic manipulation exerted by the pathogen. However, amore efficient antioxidant metabolism was able to help the wheat plants to counteract against the deleterious effects of P. oryzae infection in association with great phenylalanine ammonia lyases and polyphenoloxidases activities and high concentrations of phenolics and lignin. Based on this information, it is possible to conclude that a non- phytotoxic concentration of PA elicited the activation of host defense mechanisms that reduced blast severity. Likewise, the infection of leaves by P. oryzae induced remarkable disturbances in the primary metabolism and some of them were conserved among the cultivars regardless of their basal level of resistance to blast.

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Deshappriya, Nelum. "Xanthomonas blight of cassava : studies on bacterial pathogenicity and host resistance in vitro and in planta." Thesis, University of Bath, 1992. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332360.

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Thurston, Graham S. (Graham Stanley) 1958. "Host plant resistance and entomogenous nematodes for controlling the northern corn rootworm, Diabrotica barberi (Coleoptera: Chrysomelidae)." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66175.

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Ramsey, Andrew David. "Sources and mechanisms of host plant resistance to the cabbage whitefly, Aleyrodes proletella (L.), in brassicas." Thesis, University of Birmingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525077.

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Techniques were developed to assess germplasm from wild and commercial brassica accessions for host plant resistancet o Aleyrodesp roletella. Several wild accessionsp ossessedr esistancei n both laboratory and field experiments. Most varietal differences in preference for Brassfca oleracea cultivars were due to the host plant morphology. Resistance conferred by glossy leaves was quantitatively shown for the first time. Laboratory studiess howedt hat resistancein B. incana andB . villosa was based on an antixenotic mechanism conferred by dense downy hairs which significantly reduced oviposition. Resistance in B. spinescens and B. fruticulosa was based on an antibiotic mechanism which significantly reduced the life span of adult whiteflies and increased the mortality of the larval stages. The feeding of A. proletella was assessedu sing electrical penetration graph techniques. Feeding duration was shorter on B. fruticulosa than the susceptible control. In addition, A. proletella styletsd id not penetratem esophylcl ells,t he importanceo f this in relationt o virus transmission is discussed. Stylet activity of larval whiteflies was greater on both B. spinescens and B. fruticulosa than a susceptible control indicating problems in finding or remaining within the phloem. Some aspects of the relations between larval whiteflies and their hosts are discussed

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Kumarasinghe, Nimal Chandrakantha. "Host plant resistance in sugarcane Saccharum officinarum to the lophophid planthopper Pyrilla perpusilla Walker (Homoptera: Lophopidae)." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295250.

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Spiers, James Davis. "The effects of nutrient availability on the host plant resistance of gerbera to western flower thrips." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2525.

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Hall, Benjamin. "Plant pathogen effector proteins and their host targets : functional studies and manipulation to generate enhanced resistance." Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/62310/.

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As global population expands, so does its demand for food. This will require vast amounts of plant-derived calories. This increased pressure means it is vital that we do more with less; less land, less water, less chemical input and less labour. One major threat to crop production is posed by plant pests and pathogens. In particular, filamentous plant pathogens – oomycetes and fungi – are among the most devastating organisms known to agriculture. With their rapidly evolving genomes which specialise in breaking plant immune systems and chemical control methods, control of these pathogens is becoming extremely problematic. Especially as they often encounter crops in monoculture. An often overlooked potential strategy for developing pathogen resistance is manipulation of the host targets of plant pathogen effector proteins. In order to manipulate such targets to condition enhanced resistance, one must first develop a sound understanding of the interaction between effector and target, the target’s function in planta and which processes are being perturbed by the interaction. A previously discovered interaction between a P. infestans RXLR effector and a host MAPK known to be a positive regulator of immunity, where the effector acts to perturb positive regulation of immunity, is used here to investigate the possibility of manipulating a host target for enhanced immunity. Effector-insensitive variants were produced and characterised, prior to expression in CRISPR-edited tomato plants. We tentatively suggest that at least one variant may condition enhanced resistance. Another interactor of the same effector protein was investigated for its role in immunity and evidence suggesting it may function as a helper of the effector is presented. Additionally, the expression, purification and crystallisation of native and heavy atom derivatives of a candidate effector protein from B. graminis f.sp. hordeii is demonstrated.

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Bartaula, Radhika. "Genetic Dissection of Non-host Resistance to the Wheat Stem Rust Pathogen, Using an Interspecific Barberry Hybrid." Thesis, University of New Hampshire, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10931789.

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Stem rust, caused by the macrocyclic fungal pathogen P. graminis (Pg), is one of the most devastating diseases of wheat and other small grains globally; and the emergence of new stem rust races virulent on deployed resistance genes brings urgency to the discovery of more durable sources of genetic resistance. Given its intrinsic durability and effectiveness across a broad range of pathogens, non-host resistance (NHR) presents a compelling strategy for achieving long-term rust control in wheat. However, NHR to Pg (Pg-NHR) remains largely unexplored as a protection strategy in wheat, in part due to the challenge of developing a genetically tractable system in which Pg-NHR segregates. In this dissertation, an investigation of Pg-NHR is undertaken via the pathogen's alternate (sexual) host, barberry ( Berberis spp.). Within the highly diverse Berberis genus, numerous species function as alternate hosts to Pg but others are non-hosts. European barberry (B. vulgaris L.), for example, is susceptible to Pg infection but Japanese barberry (B. thunbergii DC.) is a non-host. In this study, the nothospecies B. ×ottawensis C.K. Scheid, an inter-specific hybrid between Pg-susceptible B. vulgaris and Pg-resistant B. thunbergii, is explored as a possible means of mapping the gene(s) underlying the apparent Pg-NHR exhibited by B. thunbergii. The overall goal of this research is to contribute to the global search for novel sources of potentially durable stem rust resistance genes.

The first chapter describes a field study conducted in western Massachusetts, in which a natural population of B. ×ottawensis was characterized to determine if the hybrid can be used to genetically dissect the Pg-NHR exhibited by B. thunbergii. A population of 63 B. ×ottawensis individuals were clonally propagated, phenotyped for disease response to Pg via controlled inoculation using overwintered telia of Pg found on naturally infected E. repens, and genotyped using the de novo genotyping-by-sequencing (GBS) pipeline GBS-SNP-CROP. Controlled inoculation of a subset of 53 B. ×ottawensis accessions, verified via GBS to be true, first-generation hybrids, revealed 51% susceptible, 33% resistant, and 16% intermediate phenotypes. Although such variation in disease response within a natural population of F₁ hybrids could be explained by non-nuclear (cytoplasmic) inheritance of resistance, a similar pattern of segregation was observed in a population of B. ×ottawensis full-sibs, developed via controlled crosses. The results of this first chapter demonstrate not only that the Pg-NHR observed in B. thunbergii segregates among F₁ interspecific hybrids with Pg-susceptible B. vulgaris but that the resistance is likely nuclearly inherited. Therefore, at least in principle, the gene(s) underlying Pg-NHR in B. thunbergii should be mappable in an F₁ population derived from the controlled hybridization of the two parental species.

Building on the results of first chapter, the second chapter of this dissertation details the generation and use of a bi-parental B. ×ottawensis mapping population to develop genetic linkage maps for both parental species and begin mapping the gene(s) underlying Pg-NHR in B. thunbergii. Using 162 full-sib F₁ hybrids and a total of 15,411 sequence variants (SNPs and indels) identified between the parents via GBS, genetic linkage maps with 1,757 and 706 markers were constructed for B. thunbergii accession 'BtUCONN1' and B. vulgaris accession 'Wagon Hill', respectively. In each map, the markers segregated into 14 linkage groups, in agreement with the 14 chromosomes present in these Berberis spp. The total lengths of the linkage maps were 1474 cM (B. thunbergii) and 1714 cM (B. vulgaris), with average distances between markers of 2.6 cM and 5.5 cM. QTL analysis for Pg resistance led to the identification of a single QTL, dubbed QPgr-3S, on the short arm of chromosome 3 of B. thunbergii. The peak LOD score of QPgr-3S is 28.2, and the QTL spans 13 cM, bounded by the distal SNP marker M411 and proximal SNP marker M969. To gain further insight into the QPgr-3S region, a chromosome-level 1.2 Gb draft genome for B. thunbergii was assembled using long PacBio reads and Hi-C data. By anchoring the B. thunbergii linkage map to the draft genome, the 13 cM Q Pgr-3S region was found to correspond to ~3.4 Mbp, represented by 10 contigs. Using a 189.3 Mb transcriptome assembled from a multiple tissue library of RNA-seq data, the QPgr-3S region was found to contain 99 genes. To help narrow this list to candidate genes of highest priority for subsequent investigation, a combination of approaches was taken. Specifically, annotation of the QTL region and differential gene expression analysis led to the identification of 12 candidate genes within the region. (Abstract shortened by ProQuest.)

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Lee, Dayoung. "Towards a Multifaceted Understanding of Host Resistance and Pathogenicity in Rice Sheath Blight and Blast Diseases." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555510608170391.

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Pereira, Jaqueline Magalhães [UNESP]. "Resistência de genótipos de eucalipto ao psilídeo-de-concha Glycaspis brimblecombei Moore (Hemiptera: psyllidae)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/106634.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Desde sua introdução no Brasil, em 2003, o psilídeo-de-concha Glycaspis brimblecombei Moore (Hemiptera: Psyllidae) vem ocasionando sérios danos ao eucalipto, principalmente através de desfolha, desenvolvimento de fumagina e secamento de ponteiros. Como estratégia no controle deste inseto, o uso de genótipos resistentes pode ser uma ferramenta valiosa. Neste trabalho, avaliou-se a resistência das espécies Eucalyptus camaldulensis (VM e IPEF), E. grandis e E. urophylla e dos híbridos de E. grandis x E. camaldulensis – gracam ‘HGC’ (3025 e 1277), de E. urophylla x E. camaldulensis – urocam ‘HUC’ (VM-1), de E. urophylla x E. grandis – urograndis ‘HUG’ (H-13, I-144, C-219 e GG-100) e de E. grandis (EG-01, EG-02 e EG-03) a G. brimblecombei, através de testes de atratividade, preferência para oviposição e preferência para alimentação e/ou antibiose sob condições de laboratório e campo. Foram realizados testes preliminares, a fim de verificar a ocorrência de condicionamento pré-imaginal, além de ajustar a melhor densidade para infestação com adultos para testes de atratividade e a melhor posição nas mudas para avaliações de preferência para oviposição. Em laboratório, verificou-se que os adultos de G. brimblecombei não apresentaram condicionamento pré-imaginal, independentemente do hospedeiro de criação ser o híbrido 3025 ou E. camaldulensis IPEF. As densidades de 10 e 15 adultos de psilídeo-de-concha por muda de eucalipto proporcionaram maior número de ovos. As folhas próximas ao ápice foram preferidas para oviposição, sendo que o número de ovos decresceu do ápice para a base. No teste com chance de escolha, os genótipos E. grandis, E. urophylla, C-219 e H-13 foram menos atrativos ao psilídeo-de-concha, expressando não-preferência. Em teste com chance de escolha, o número de ovos depositados nas folhas dos genótipos H-13, E. grandis...
Since its introduction in Brazil in 2003, the red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae) has been causing serious damages in eucalyptus trees, especially through defoliation, development of sooty mold and dieback. The use of resistant genotypes as a strategy to control this insect may be a valuable tool. In this study, the resistance of species Eucalyptus camaldulensis (VM e IPEF), E. grandis and E. urophylla and hybrids E. grandis x E. camaldulensis - gracam ‘HGC’ (3025 and 1277), E. urophylla x E. camaldulensis - urocam ‘HUC’ (VM-1), E. urophylla x E. grandis – urograndis ‘HUG’ (H-13, I-144, C-219 and GG-100) and E. grandis (EG-01, EG-02 and EG-03) on G. brimblecombei, through attractiveness, oviposition preference and feeding preference and/or antibiosis tests under laboratory and field conditions evaluated. Initially preliminary tests were carried out, using eucalyptus seedlings, in order to verify the occurrence of preimaginal conditioning, and also adjust the best density for adult infestation for attractiveness tests and the best position in the seedlings for the evaluation of oviposition preference. In laboratory conditions, that G. brimblecombei adults did not present preimaginal conditioning, despite the fact that the rearing host was a 3025 hybrid or E. camaldulensis IPEF. The densities of 10 and 15 psyllid adults per eucalyptus seedlings showed a higher number of eggs. The insects showed preference for the leaves close the apex for oviposition, being that the number of eggs decreased from the apex to the basis. In the choice test concerning attractiveness, genotypes E. grandis, E. urophylla, C-219 and H-13 were less attractive to psyllid, showing non-preference. In a choice test, the number of eggs oviposited in leaves of genotypes H-13, E. grandis and E. urophylla were lower when compared... (Complete abstract click electronic access below)

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Thorpe, Katherine Victoria. "The feeding ecology of the large pine weevil (Hylobius abietis L.) in relation to host plant resistance." Thesis, University of Ulster, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274135.

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Niide, Terutaka. "Development of soybean host plant resistance and other management options for the stem borer, Dectes texanus leconte." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1545.

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Gupta, Anju. "Host plant resistance genes to Fusarium head blight of wheat : sources, inheritance and determination of genetic control /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu148640228826235.

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Ripple, Brandon Wayne. "Host plant resistance to Whiteflies, Bemisia tabaci (Gennadius), Biotype B, (Homoptera: Aleyrodidae) in cotton race stocks for breeding improved cotton cultivars." Texas A&M University, 2003. http://hdl.handle.net/1969.1/239.

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Whiteflies (Bemisia tabaci, Biotype B, Homoptera: Aleyrodidae) are pests of cotton crops, affecting the yield of the crop both indirectly and directly. These pests feed on the leaves of cotton plants and produce "honeydew," a sticky liquid excretion which covers the lint of the open cotton boll creating problems during the processing of the lint. High densities of these pests also can decrease the productivity of the cotton plant by stripping it of vital nutrients. The primary objective of this research was to screen 116 converted cotton race stocks for resistance to sweetpotato whiteflies. Responses of converted race stocks to whiteflies are compared to that of known susceptible commercial cultivars PSC 355 and Delta Pearl. Screens for antibiosis resistance to whitefly were established using excised leaves placed in a nutrient solution (¼ strength Hoagland's). Cohort populations of whiteflies were established on these leaves and followed daily to determine differences in developmental time as well as percent survival. Resistant candidates were determined using a chi-squared test comparing the ranked sums of leaf averages for the two selection criteria, whitefly developmental time and percent whitefly survival, of each cotton race stock to that of the putative known susceptibles (KS). These tests showed 6 converted race stocks to be significantly different (P ≤ 0.1) from the KS for at least one of the two selection criteria. Of these converted race stocks, M-9044-0154 and M-9044-0156 showed to have lower whitefly survival than the KS, while M-9644-0188, M-9644-0195, M-0044-0221, and M-9644-0242 showed whitefly to have an increased developmental time. Retesting of these six converted race stocks along with several others identified another race stock line, M-0044-0171, which was significantly different from the KS. Retesting also indicated that M-9644-0188 was different for survival in addition to developmental time which was determined in the original screening. Additional tests were conducted in the greenhouse and field to examine these race stock lines. Greenhouse screenings indicated that M-9044-0156 and M-9644-0188 contained possible non-preference resistance characteristics. Field screenings conducted in Weslaco and College Station, TX in 2002 and 2003 failed to provide useful data due to low densities of insects.

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Rupp, Jessica Lynn Shoup. "RNA interference mediated virus resistance in transgenic wheat." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/20387.

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Doctor of Philosophy
Plant Pathology
John P. Fellers
Harold N. Trick
Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are two viruses affecting wheat in the Great Plains region of the United States. Genetic resistance is severely limited, requiring management methods focusing on the deployment of resistant varieties and various cultural practices. Evaluation of resistance is complicated by the lack of a standard rating scale. The objective of this work was to develop new avenues to mitigate these challenges. A standardized virus symptom rating scale was developed using historical Kansas rating scales, and validated using multiple wheat populations. Two independent RNA interference (RNAi) expression vectors targeting portions of viral coat protein (CP) of WSMV and TriMV were previously transformed into wheat. T₂ plants and beyond were evaluated using PCR, reverse transcription-PCR and bioassays in which plants were challenged with their respective virus. These lines were evaluated for resistance through the T₆ generation. Crosses were made with the susceptible winter wheat cultivars, ‘Overley’ and ‘Karl 92.’ Real-time PCR results show viral titer was up to 20-fold lower in the T₆ transgenic lines, the F₁, and the BC₁F₁ compared to control plants. This provides evidence that this RNAi silencing method is stable in wheat over multiple generations. WSMV and TriMV use host eukaryotic initiation factors (eIF) in order to facilitate replication of their genomes. Previously created RNAi expression vectors were derived from the sequences of the wheat genes eIF(iso)4E-2 and eIF4G. Evaluation of these lines began in the T₁ generation. Resistance has been demonstrated in three lines of eIF(iso)4E-2 and four lines of eIF4G, derived by single seed descent. T₆ progeny co-infected with WSMV and TriMV continue to be resistant. Crosses have been performed with the winter wheat ‘Karl 92’ and three Kansas elite lines, KS030887K-6, KS09H19-2-3, and KS10HW78-1-1. RNAi construct effectiveness was evaluated using real-time PCR. Results show up to 18-fold reduction in viral titer in the transgenic lines, the F₁, and the BC₁F₁ in comparison to control plants. This research provides the first evidence that a single host transgene can provide resistance to multiple viruses and has great potential benefits to both breeders and producers.

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Ellis, Margaret Lee. "The Soybean Seedling Disease Complex: Pythium spp. and Fusarium graminearum and their Management through Host Resistance." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322495401.

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Steenkamp, Sonia. "Host plant resistance as a management tool for Ditylenchus africanus (Nematoda: Tylenchidae) on groundnut (Arachis hypogaea) / Sonia Steenkamp." Thesis, North-West University, 2008. http://hdl.handle.net/10394/2299.

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Sonawala, Unnati Subhash. "Understanding the role of host amino acid transporters in nutrient acquisition by oomycete pathogens." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/102868.

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Hyaloperonospora arabidopsidis (Hpa) is a naturally occurring oomycete pathogen on Arabidopsis thaliana. It is related to downy mildews of economically important crops such as cabbage, kale and broccoli, belonging to the Brassicaceae family. Downy mildew pathogens are obligate biotrophs that extract nutrients exclusively from living plant cells. As a part of its obligate biotrophy lifestyle, Hpa has lost the ability to assimilate inorganic nitrogen and sulfur. It thus has to acquire these nutrients from the host in an organic form; possibly amino acids. Using a reverse genetic approach, I was able to identify two host amino acid transporters that are up-regulated during Hpa infection: AAP3 and AAP6. Both of these transporters are localized in the vasculature of the plant, AAP3 mostly in the root, and AAP6 in the roots and shoots. Using transgenic lines of Arabidopsis containing transcriptional and translational reporter fusion constructs for these genes, I found that AAP3 displays increased mRNA accumulation which is attributable to an increased promoter activity in regions of shoot tissue colonized by Hpa. On the other hand, AAP6 displays a mild increase in mRNA accumulation under Hpa infection, but the induction becomes more prominent at the protein level as seen by fluorescence from GFP fused to AAP6. Surprisingly, null mutants of AAP3 did not impact Hpa growth whereas null mutants of AAP6 made the plant more susceptible to Hpa. Furthermore, aap6 mutants accumulate fewer free amino acids in the phloem compared to wild-type plants when infected with Hpa. Together, these results suggest that AAP6 acts a nutritional starvation gene for the pathogen and hence aids the plant during infection. While we now know more about AAP3's regulation during infection, its function remains to be elucidated. To successfully colonize a plant, a pathogen must be able to achieve both suppression of plant immunity and acquisition of nutrients from the plant host. While the former has been well studied, research on the latter is sparse. This work was a step in the direction to increase our understanding of potential players in nutrient acquisition by pathogens.
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Dossa, Codjo Sylvestre Gerbert [Verfasser]. "Climate change and host plant resistance : deffects of high temperature and drought on rice R genes' mediated resistance to bacterial blight / Codjo Sylvestre Gerbert Dossa." Hannover : Technische Informationsbibliothek (TIB), 2016. http://d-nb.info/1100287647/34.

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Dossa, Gerbert Sylvestre [Verfasser]. "Climate change and host plant resistance : deffects of high temperature and drought on rice R genes' mediated resistance to bacterial blight / Codjo Sylvestre Gerbert Dossa." Hannover : Technische Informationsbibliothek (TIB), 2016. http://d-nb.info/1100287647/34.

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Jesus, Flávio Gonçalves de [UNESP]. "Resistência de genótipos de feijoeiro ao ataque de Bemisia tabaci (Genn.) Biótipo B (Hemiptera: Aleyrodidae) e Caliothrips phaseoli (Hood.) (Thysanoptera: Thripidae)." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/91364.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Avaliou-se o comportamento de genótipos de feijoeiro dos tipos de grãos carioca e preto nas épocas de cultivo “das águas”, “da seca” e “de inverno” e grãos dos tipos especiais na época “da seca” sob a infestação de Bemisia tabaci (Genn.) biótipo B e Caliothrips phaseoli (Hood.) e a associação de genótipos e inseticidas no controle destas pragas em condições de campo. Utilizaram-se os genótipos IAC-Carioca Tybatã, IAC Una, FT-Nobre, Pérola, Gen 96A98-15-3-32-1, Gen 96A45-3-51-52-1, IAC Alvorada, IAC Diplomata, Gen 96A3-P1-1-1, LP 98-122, LP 02- 130, LP 01-38, LP 9979, BRS-Pontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48, Z-28 para os tipos carioca e preto e IAPAR 31, Rosinha G2, Jalo precoce, Pérola, IAC Harmonia, Gen 99TGR110, Gen 99TG2868, Gen 99TGR3416, Gen 99TG3450, Gen 99TG823, Gen 99TGR609, IAC Jaraguá, Gen 95A10061531, Gen 99TGR3114 e Gen 96A1473153V2 para os grãos dos tipos especiais. Com relação ao comportamento dos genótipos dos tipos carioca e preto, os menos ovipositados pela B. tabaci biótipo B foram IAC Una, LP 98-122, BRS-Pontal, Pérola, Gen 96A45 3-51-52-1 e BRS-Triunfo. As menores presenças de ninfas de mosca branca foram observadas em LP 01-38 e IAC Alvorada e maiores em Z - 28. C. phaseoli foi encontrado em menor número em BRS-Triunfo, LP 9979, LP 98-122 e BRS-Requinte e maior número nos genótipos LP 02-130, BRS-Grafite, IAC Alvorada e IAC Diplomata. Para os grãos dos tipos especiais, os genótipos menos ovipositados pela B. tabaci biótipo B foram IAC Harmonia, Pérola, Gen TG3114 e Gen 95A10061531, enquanto os mais ovipositados destacaram IAC Jaraguá e Gen 99TG3450; as menores infestações de ninfas de B. tabaci biótipo B foram observadas em Pérola e IAC Harmonia e maior em IAC Jaraguá; e, todos os genótipos foram suscetível ao C. phaseoli...
The comportment of bean genotypes carioca and black grain was evaluated on field conditions on the water, dry and winter season and bean genotypes special type grains on dry season and under the infestation of Bemisia tabaci (Genn.) biotype B and Caliothrips phaseoli (Hood) and of common beans genotypes associated or not the insecticides use this pest in field conditions. The genotypes used were: IACCarioca Tybatã, IAC-Una, FT-Nobre, Pérola, Gen 96A98-15-3-32-1, Gen 96A45-3-51- 52-1, IAC Alvorada, IAC Diplomata, Gen 96A3-P1-1-1, LP 98-122, LP 02-130, LP 01-38, LP 9979, BRS-Pontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48, Z-28 for the type carioca and black grains and IAPAR 31, Rosinha G2, Jalo precoce, Pérola, IAC Harmonia, Gen 99TGR110, Gen 99TG2868, Gen 99TGR3416, Gen 99TG3450, Gen 99TG823, Gen 99TGR609, IAC Jaragua, Gen 95A10061531, Gen 99TGR3114 e Gen 96A1473153V2 for the type special grain. With relation at comportment carioca and black grain, the less oviposition genotypes by B. tabaci biotype B were IAC Una, LP 98- 122, BRS-Pontal and Perola, while the most oviposited were Gen 96A45 3-51-52-1 and BRS-Triunfo. The less presence of nymphs of whitefly were observed on LP 01-38 and IAC Alvorada and the most at Z-28. C. phaesoli was found in less number on BRSTriunfo, LP 9979, LP 98-122 and BRS-Requinte and more on the LP 02-130, BRSGrafite, IAC Alvorada and IAC Diplomata genotypes. For the type special grain, the less oviposition genotypes by B. tabaci biotype B were IAC Harmonia, Pérola, Gen TG3114 e Gen 95A10061531, while the most oviposited were IAC Jaraguá and Gen 99TG3450; the less presence of nymphs of whitefly was observed on Pérola and IAC Harmonia and the most at IAC Jaraguá; every genotypes were susceptible to attack of C. phaseoli; when associated insectised with genotypes, less oviposition genotypes by B. tabaci biotype B were LP 9979 and IAC Jaragua,... (Complete abstract, click electronic access below)

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47

Lynch, Margaret Emma. "Host plant-mediated interspecific competition via induced resistance interactions between the potato leafhopper and the Colorado potato beetle /." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2549.

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Thesis (M.S.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Dept. of Entomology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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48

Bahlmann, Lieschen. "Factors affecting the resistance mechanisms of the Russian wheat aphid (Diuraphis noxia) on wheat." Diss., University of Pretoria, 2002. http://hdl.handle.net/2263/28470.

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Banito, Agnassim. "Integrated control of cassava bacterial blight in West Africa in relation to ecozones, host plant resistance and cultural practices." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969263562.

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Okonkwo, N. J. "The effects of host-plant resistance in Vicia faba (L.) on the susceptibility of Aphis fabae (Scop.) to insecticides." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/47504.

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Dissertations / Theses on the topic 'Host resistance in plants'

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