Academic literature on the topic 'Plant varieties ; Phytopathogenic microorganisms'

Global climate warming and involvement of new regions with endemic populations of microorganisms in commercial seed production have led to an increase in the diversity of phytopathogenic bacteria that are affecting major crops, including the fruit trees. As a rule, emergence of new pathogens is associated with importation of infected seeds and planting material, cultivation of new species and varieties of plants, and expansion of agricultural trade with foreign countries. One of the leaders in diversity among phytopathogens is the genus Xanthomonas bacteria, affecting more than 400 plant species. Among the characteristic signs of xanthomonads is the high frequency of horizontal gene transfer both within the genus and between phylogenetically removed bacterial taxa – up to 25% of the genes are of this origin. In this paper, we consider another source of increasing the number of phytopathogenic species – by the epiphytic populations. These bacteria are the likely ancestral form of the phytopathogenic bacteria of the genus Xanthomonas.

Monitoring studies were carried out according to generally accepted methods in the northern forest-steppe of West Siberia in 2019–2020, using the varieties collection of the Institute of Cytology and Genetics SB RAS. Studies have shown that the genotypes of spring wheat varieties had a significant impact on the functioning of the “plant-phytopathogensaprotrophs” system. The parasitic activity of phytopathogens (Bipolaris sorokiniana Sacc. Shoem., Fusarium spp. Link.) differed in the varietal groups to 43.6 %. Varieties of Asian origin (China, India, Kazakhstan, Syria) were most affected by the root infections, Australian varieties were least affected by phytopathogens, due to the chemical composition of root exudates, which suppressed the number of parasitic and saprotrophic microorganisms. Varietal secretions of the wheat plants roots regulated the number of saprotrophic rhizospheric microorganisms. The share of the influence of the “variety” factor on the number of saprotrophic soil microorganisms was 24.3 % and was reliable at a 1 % level. The most sensitive to the composition and number of root exudates of wheat plants turned out to be bacteria of various trophic groups, the most resistant were micromycetes. In comparison with the background indices of non-rhizospheric soil, the number of cellulosolytic bacteria increased up to 3 times (West European varieties), bacteria consuming organic nitrogen – up to 5.6 times (Asian varieties), consumers of organic nitrogen forms – up to 2.9 times (West European varieties), oligonitrophilic bacteria – up to 12.7 times (Siberian varieties). Varieties far from the region of the study (Australia, Africa, America) exerted a repressive effect on the trophic groups of microorganisms, reducing their number in comparison with indicators of non-rhizospheric soil.

The results of studies on the presence in the seeds of legumes and cereals of protein inhibitors that are active against animal proteinases (trypsin) and exogenous peptidases of phytopathogenic microorganisms are presented. It has been shown that secreted proteolytic enzymes of the studied phytopathogens are mainly represented by cysteine proteinases, to a lesser extent, serine and aspartane proteinases are present. It has been established that a close positive correlation between plant resistance to pathogens is observed not with well-known and widespread trypsin inhibitors, but with the activity of inhibitors directed against exogenous peptidases secreted by fungal pathogens of the genus Fusarium, Colletotrichum and Helminthosporium. The results obtained in the course of the work can be used in breeding and genetic studies on the creation of varieties and types of crops with increased resistance to pathogenic microflora and insect pests, as well as to create protective preparations.

The results of researches of influence of raspberry plant varieties on the species composition of micromycetes in rhizospheric soil and on vegetative organs of plants in the conditions of organic production are given. The mycobiota of raspberry varieties Joan J and Himbo-Top during plant ontogenesis was analyzed and the species composition of phytopathogenic micromycetes in the rhizosphere and on plant leaves was established. It was found that the population is dominated by fungi of following species: Septoria rubi, West, Botrytis cinerea, Pers, Aspergillus niger, V. Tiegh, Alternaria alternata, (Fr.) Keissl., Fusarium graminearum, Schwabe, regardless of the phase of ontogenesis of plants that produce mycotoxins, and can cause disease in animals and humans. According to the results of research, it can be assumed that in the phase of inflorescence growth in the mycobiota of rhizospheric soil and on the vegetative organs of raspberry plants of Joan J and Himbo-Top the greatest competitiveness can be characterized by isolates of fungi Septoria rubi and Alternaria alternata. The obtained results indicate a significant differentiation of the studied varieties by the reaction of interaction between plants, microorganisms and the environment. Thus, while in the mycobiota of rhizospheric soil and vegetative organs of raspberry plants of the Joan J variety during intensive fruiting of plants the isolates of Aspergillus flavus fungi were characterized by the greatest competitiveness, in Himbo-Top cultivar the highest rates of radial growth were shown by isolates of Aspergillus oryzae and Alternaria alternata

A significant part of the used pesticides does not reach the target organisms and, while remaining in the agrophytocenosis, influences all living organisms in it. Having a toxic and often mutagenic effect, pesticides induce morphological and physiological changes in the cells of microorganisms and are the cause of phenotypic heterogeneity of their populations. However, the effect of pesticides on phytopathogenic bacteria as non-target microorganisms remains out of the field of view for most researchers. However, the use of pesticides can lead to expansion of the diversity of existing phytopathogens and, as a consequence, complications of identification of the pathogens, loss of resistance by plants varieties, and increased harm from diseases caused by them. This study is focused on the effect of pesticides used in tomato plantations on the causative agent of bacterial speck of this crop—Pseudomonas syringae pv. tomato. The studies were carried out using the methods of classical microbiology. The mutagenic action of pesticides was recorded, taking into account the increase of the number of streptomycin resistance mutations in bacteria in the case of pesticide action. It is established that the fungicide aluminium phosethyl is characterised by a bacteriostatic effect on P. syringae pv. tomato. Deltamethrin insecticide does not affect the growth of P. syringae pv. tomato. However, there is an increase in the frequency of streptomycin resistance mutations in both studied strains of P. syringae pv. tomato after using deltamethrin. It is shown that the frequency of occurrence of R (rough colonies) forms of P. syringae pv. tomato IZ28 and IZ46 after using deltamethrin increased by 100 times when in comparison to the frequency of spontaneous morphological dissociation, or smooth-to-rough (S-R) mutation, of these bacteria. Therefore, aluminium phosethyl is characterised by moderate bacteriostatic action against P. syringae pv. tomato. Deltamethrin does not influence the growth of the pathogen of tomato speck but increases the frequency of formation of StrR mutants and R forms of phytopathogenic bacteria.

The article considers studies designed to justify the types of pathogens of tomatoes that occur during vegetation and storage, and measures to combat them. The work was carried out in 2019 on a land plot near the rural districts of Babaykorgan, Zhuynek, and Issa of the Turkestan region. As it became known, the growth period of vegetable seedlings depends on the temperature of the soil. In our experience, the seed material was planted in the open ground in early April. The soil was very hot and moist. Depending on the culture and varietal characteristics, the sprouts appeared on 6-15 days after sowing. The results of phytopathological control showed that various varieties of all types of tomatoes were affected by phytopathogenic microorganisms. During the growing season, the most dangerous disease in tomato fruit was apical rot of the fruit, which led to a significant decrease in the yield. The leaves are widely developed early blight and verticillus. Late blight at the end of the growing season was observed in full on both leaves and fruits (developed during fruit storage). When growing tomato crops at two sites was dominated by late blight, early blight, verticillus, viral diseases and apical rot. Based on the results of phytopathological control, it can be concluded that the number of fungal diseases prevailed in plot 1, which is associated with frequent irrigation on this site, its shading and a large number of fruits on plants. Viral diseases prevailed in plot 2, which is explained by weeds clogging the plot.

Trichoderma species are opportunistic plant symbionts that are common in the root and rhizosphere ecosystems. Many Trichoderma species may enhance plant growth, nutrient acquisition, and disease resistance, and for these reasons, they are widely used in agriculture as biofertilizers or biocontrol agents. Host plant genotype and other microorganisms, such as root pathogens, may influence the efficacy of Trichoderma inoculants. Aphanomyces euteiches is an important soil-borne oomycete in western Canada that causes root rot in legume crops such as lentil and pea, and there is not yet any significantly resistant varieties or effective treatments available to control the disease. In this study, the composition of root-associated fungal communities and the abundance of Trichoderma species, T. harzianum strain T-22 and T. virens strain G41, was determined in the roots of eight Lens genotypes based on internal transcribed spacer (ITS) Illumina MiSeq paired-end sequencing, both in the presence and the absence of the root rot pathogen Aphanomyces euteiches. Biocontrol effects of T. harzianum on A. euteiches was also examined. Significant genotypic variations were observed in the composition of root-associated fungal communities and the abundance of the different Trichoderma species in the lentil roots. The presence of A. euteiches altered the composition of Trichoderma found associated to the lentil genotypes. Biocontrol of A. euteiches by T. harzianum T22 species was observed in vitro and positive correlations between the abundance of Trichoderma and plant root and shoot biomass were observed in vivo. These findings revealed that lentil genotype and infection by the phytopathogen A. euteiches greatly influenced the colonization of root-associated fungi and the abundance of the Trichoderma species, as well as the effect on plant growth promotion. The multipartite interactions observed among lentil genotypes, Trichoderma species and A. euteiches suggest possibilities to select compatible host-beneficial microbe combinations in lentil breeding programs and to develop application strategies to harness the beneficial effects of Trichoderma inoculants in sustainable crop production systems.

Nanotechnology is highly interdisciplinary and important research area in modern science. The use of nanomaterials offer major advantages due to their unique size, shape and significantly improved physical, chemical, biological and antimicrobial properties. Physicochemical and antimicrobial properties of metal nanoparticles have received much attention of researchers. There are different methods i.e. chemical, physical and biological for synthesis of nanoparticles. Chemical and physical methods have some limitations, and therefore, biological methods are needed to develop environment-friendly synthesis of nanoparticles. Moreover, biological method for the production of nanoparticles is simpler than chemical method as biological agents secrete large amount of enzymes, which reduce metals and can be responsible for the synthesis and capping on nanoparticles. Biological systems for nanoparticle synthesis include plants, fungi, bacteria, yeasts, and actinomycetes. Many plant species including Opuntia ficus-indica, Azardirachta indica, Lawsonia inermis, Triticum aestivum, Hydrilla verticillata, Citrus medica, Catharanthus roseus, Avena sativa, etc., bacteria, such as Bacillus subtilis, Sulfate-Reducing Bacteria, Pseudomonas stutzeri, Lactobacillus sp., Klebsiella aerogenes, Torulopsis sp., and fungi, like Fusarium spp. Aspergillus spp., Verticillium spp., Saccharomyces cerevisae MKY3, Phoma spp. etc. have been exploited for the synthesis of different nanoparticles. Among all biological systems, fungi have been found to be more efficient system for synthesis of metal nanoparticles as they are easy to grow, produce more biomass and secret many enzymes. We proposed the term myconanotechnology (myco = fungi, nanotechnology = the creation and exploitation of materials in the size range of 1–100 nm). Myconanotechnology is the interface between mycology and nanotechnology, and is an exciting new applied interdisciplinary science that may have considerable potential, partly due to the wide range and diversity of fungi. Nanotechnology is the promising tool to improve agricultural productivity though delivery of genes and drug molecules to target sites at cellular levels, genetic improvement, and nano-array based gene-technologies for gene expressions in plants and also use of nanoparticles-based gene transfer for breeding of varieties resistant to different pathogens and pests. The nanoparticles like copper (Cu), silver (Ag), titanium (Ti) and chitosan have shown their potential as novel antimicrobials for the management of pathogenic microorganisms affecting agricultural crops. Different experiments confirmed that fungal hyphae and conidial germination of pathogenic fungi are significantly inhibited by copper nanoparticles. The nanotechnologies can be used for the disease detection and also for its management. The progress in development of nano-herbicides, nano-fungicides and nano-pesticides will open up new avenues in the field of management of plant pathogens. The use of different nanoparticles in agriculture will increase productivity of crop. It is the necessity of time to use nanotechnology in agriculture with extensive experimental trials. However, there are challenges particularly the toxicity, which is not a big issue as compared to fungicides and pesticides.

The number phytopathogenic micromycetes is determined in the seeds of such cultivated varieties of cultural plant as soybeans, sunflowers, yellow mustard, buckwheat and thistle, which are grown by organic technology. It is shown that the number of micromycetes in the plant seeds differs significantly and ranges from 0.2 to 1.3 thousand NCO/g seeds. It depends on properties plants variety and hybrid, which are characterized by some certain set of physiological and biochemical characteristics that influences the formation seed mycobiome and it is quantitative composition. In the seeds varieties of these crops we identified such species of the phytopathogenic fungi as Alternaria alternate Fr., Fusarium oxysporum Schleht, Cladosporium herbarum Lket Gray, Botrytiscinerea Pers. Ex Fr., Ascochyta fagopyri Bres., Alternaria tenuissima (Kunze) Wiltshire, Aspergillus P. Micheliex Haller, Pénicillium Link. It was found that the species composition of phytopathogenic micromycetes in the seeds of soybean cultivar Kent and thistle Riches is much more diverse than the seeds other crops dominated by fungi A. alternate and F. oxysporum, which are characterized by different frequency of occurrence. These phytopathogenic fungi can cause plant diseases at different stages of ontogenesis, produce mycotoxins and reduce the quality of plant products. In the mycobiome of seeds buckwheat varieties Sophia, Sуn and sunflower hybrids Oscar and Oliver are dominated by fungi of the genus Pénicillium аnd Aspergillus (60–90%). The seeds affected by saprotrophic fungi can be reinfected during storage. This reduces its field and laboratory germination of the seeds. Saprotrophic fungi that dominate the seeds significantly impair its quality during storage and cause dangerous plant diseases in agrophytocenoses during the cultivation of this variety/hybrid. This requires the application of additional preventive protection measures of plants. Mycobioma mustard seeds of а yellow variety Ford represents a small number the phytopathogenic micromycetes. This may indicate its environmental safety in organic production. Thus, the analyzed research results indicate a significant differentiation in varieties species as to composition and number of phytopathogenic species of micromycetes in the seed mycobioma. Therefore, in order to avoid ecologic risks and biological contamination of agrocenoses, it is necessary to test the seeds, as on the density of the mycobiome and on the frequency of phytopathogenic micromycetes damage.

The defence mechanisms expressed in roots of Pinus sylvestris seedlings challenged with fungal pathogens were investigated, and a comparison was made between the expression of defences in non-mycorrhizal and mycorrhizal seedlings. Papillae were formed by cortical cells of non-mycorrhizal seedlings infected with Cylindrocarpon destructans. Histochemical evidence was obtained for pectic materials comprising an important polysaccharide component of these structures, and for the deposition of polyphenolic compounds also. Proton induced X-ray emission (PIXE) microanalysis indicated that insoluble calcium levels were elevated in papillae relative to normal cell walls. Although papillae appeared important in protecting cortical cells against penetration by fungal hyphae, a primary role for the wall appositions in the resistance of seedlings of Scots pine against root pathogens could not be proven. Although phytoalexins were not detected in the roots of Scots pine seedlings following infection with C. destructans, the mean content of an abietic acid fraction (comprising six compounds, of which only dehydroabietic acid could be positively identified), increased from 5.2 to 9.7mg g^-1 dry weight. This fraction exhibited some antifungal activity. -related proteins induced de novo by infection could not be detected, but several constitutive apoplastic proteins, including some with chitinase activity, appeared to increase in the needles of root-infected seedlings. The formation of ectomycorrhizae with Pisolithus tinctorius, Suillus bovinus and Hebeloma crustuliniforme did not itself induce papilla formation in the roots of P. sylvestris. Evidence was obtained to suggest that the response was suppressed when mycorrhizal seedlings were challenged with C. destructans. Results highly suggestive of the induction of systemic resistance in P. sylvestris seedlings, consequent upon mycorrhizal infection, were obtained. In seedlings grown in vitro the survival rate of mycorrhizal seedlings challenged aerially with Botrytis cinerea was 37.5% compared with 7.1 in seedlings grown gnotobiotically. However, the physiological mechanisms by which this protection was imparted remain to be determined.

Thesis (MScAgric )--Stellenbosch University, 2004.
ENGLISH ABSTRACT: In an attempt to combat some of the pathogens that are associated with trunk diseases and disorders of grapevines, research in this thesis focused on the taxonomy and pathological aspects of Coniellai/Pilidiella, Botryosphaeria and Phomopsis spp. Previously, conidial pigmentation was used to separate Pilidiella from Coniella. Recently, however, the two genera have been regarded as synonymous, with the older name, Coniella, having priority. The most important species in the Coniellai/Pilidiella complex of grapevines is C. diplodiella (Speg.) Petr. & Syd., the causal organism of white rot of grapevines. Previous studies found it difficult to distinguish between C. diplodiella and C. fragariae (Oudem.) B. Sutton, which is known to occur in soil and caused leaf diseases of Fragaria and Eucalyptus. Both these species have previously been reported from South Africa. None of the reports on C. diplodiella could be scientifically substantiated; therefore it is still a quarantine organism. However, this status has been questioned. Based on sequence analyses of the internal transcribed spacer region (ITS 1, ITS 2), 5.8S gene, large subunit (LSU) and elongation factor 1- α gene (EF l- α) from the type species of Pilidiella and Coniella, Coniella was separated from Pilidiella, with the majority of taxa residing in Pilidiella. Pilidiella is characterised by species with hyaline to pale brown conidia (avg. length: width >1.5), with Coniella having dark brown conidia (avg. length: width ≤1.5). Pilidiella diplodiella, previously C. diplodiella, causal organism of white rot of grapevines, was shown to be an older name for C. petrakii. This fungus is present in South Africa and is therefore no longer of quarantine importance. Based on analyses of the histone (H3) gene sequences of isolates in the P. diplodiella species complex, P. diplodiella was separated from a newly described species, P. diplodiopsis. A new species, P. eucalyptorum, is proposed for isolates formerly treated as C. fragariae, associated with leaf spots of Eucalyptus spp. This species clustered basal to Pilidiella, and may represent yet a third genus within this complex. Pilidiella destruens was newly described as anamorph of Schizoparme destruens, which is associated with twig dieback of Eucalyptus spp. in Hawaii. The genus Botryosphaeria Ces. & De Not. are known to be cosmopolitan, with broad host ranges and geographical distributions. Several saprotrophic species have been reported from grapevines, while others are severe pathogens of this host. These species include B. dothidea (Moug.: Fr.) Ces. & De Not., B. parva Pennycook & Samuels, B. obtusa (Schwein.) Shoemaker, B. stevensii Shoemaker, B. lutea A.J.L. Phillips and B. ribis Grossenb. & Duggar. Species reported from South Africa as grapevine pathogens are B. obtusa, B. dothidea, B. ribis and B. vitis (Schulzer) Sacco. In the present study, morphological, DNA sequence data (ITS 1, 5.8S, ITS 2 and EFI-α) and pathological data were used to distinguish 11 Botryosphaeria spp. associated with grapevines from South Africa and other parts of the world. Botryosphaeria australis, B. lutea, B. obtusa, B. parva, B. rhodina and a Diplodia sp. were confirmed from grapevines in South Africa, while Diplodia porosum, Fusicoccum viticlavatum and F. vitifusiforme were described as new species. Although isolates of B. dothidea and B. stevensii were confirmed from grapevines in Portugal, neither of these species, nor B. ribis, were isolated in this study. All grapevine isolates from Portugal, formerly presumed to be B. rib is, are identified as B. parva based on EF1-α sequence data. Artificial inoculations on grapevine shoots showed that B. australis, B. parva, B. ribis and B. stevensii are more virulent than the other species studied. The Diplodia sp. collected from grapevine canes was identified as morphologically similar, but phylogenetically distinct from D. sarmentorum, while D. sarmentorum was confirmed as anamorph of Otthia spiraeae, the type species of the genus Otthia (Botryosphaeriaceae). A culture identified as O. spiraeae clustered within Botryosphaeria, and is thus regarded as a probable synonym. These findings confirm earlier suggestions that the generic concept of Botryosphaeria should be expanded to include genera with septate ascospores and Diplodia anamorphs. The genus Phomopsis (Sacc.) Bubak contains many species that are plant pathogenic or saprotrophic. Ten species are known from grapevines. However, only two have been confirmed as being pathogenic, namely P. viticola (Sacc.) Sacc., causal organism of Phomopsis cane and leaf spot and P. vitimegaspora Kuo & Leu (teleomorph Diaporthe kyushuensis Kajitani & Kanem.), causal organism of swelling arm disease of grapevines. P. amygdali (Delacr.) 1.1. Tuset & M.T. Portilla, a known pathogen from Prunus sp., was shown to be a possible pathogen of grapevines in a previous study. D. perjuncta Niessl. causes bleaching of dormant canes only and is therefore of little importance as a grapevine pathogen. Recently a number of Phomopsis isolates were obtained from grapevines in the Western Cape province of South Africa. Isolations were made from Phomopsis-like symptoms, pruning wounds and asymptomatic nursery plants. These isolates showed great variation in morphology and cultural characteristics. Earlier taxonomic treatments of Phomopsis, based species identification on host specificity, cultural characteristics and morphology. Recent studies have indicated that these characteristics can no longer be used to distinguish species of Phomopsis due to wide host ranges and morphological plasticity of some species. The use of anamorph/teleomorph relationships in species identification is also untenable, since Diaporthe teleomorphs have only been described for approximately 20% of the known Phomopsis species. In this study morphological data, DNA sequences (ITS-I, 5.8S, ITS-2) and pathogenicity data were combined to distinguish Phomopsis spp. from grapevines. Fifteen species of Phomopsis were delineated by phylogenetic analysis of ITS sequence data. Diaporthe helianthi, a sunflower pathogen, was reported from grapevines for the first time, with a further six, unknown species also distinguished. Three different clades contained isolates previously identified as D. perjuncta. Based on type studies, it appeared that the name D. viticola was available for collections from Portugal and Germany, a new species, D. australafricana, was proposed for South African and Australian isolates, formerly treated as D. perjuncta or D. viticola. An epitype specimen and culture were designated for D. perjuncta. This species was distinguished from D. viticola and D. australafricana based on morphology and DNA phylogeny. Artificial inoculations of green grapevine shoots indicated that, of the species tested, P. amygdali, a known pathogen of peaches in the USA, and P. viticola were the most virulent.
AFRIKAANSE OPSOMMING: In 'n poging om sommige patogene geassosieer met stamsiektes en syndrome, te beveg, het die navorsing in die tesis gefokus op die taksonomie en patologiese aspekte van ConiellaiPilidiella, Botryosphaeria en Phomopsis spp Voorheen is konidium pigmentasie gebruik om Pilidiella (hialien tot ligbruin konidia) van Coniella (donkerbruin konidia) te skei. Onlangs is hierdie twee genera egter as sinoniem beskou met die ouer naam, Coniella, wat voorkeur gekry het. Die belangrikste spesies in die ConiellaiPilidiella kompleks van wingerd is C. diplodiella (Speg.) Petr. & Syd., die veroorsakende organisme van witvrot van wingerd. Vorige studies het dit moeilik gevind om te onderskei tussen C. diplodiella en C. fragariae (Oudem.) B. Sutton, wat bekend is dat dit in grond voorkom en ook blaarsiektes van Fragaria en Eucalyptus veroorsaak. Beide hierdie spesies is tevore in Suid-Afrika aangemeld. Geen van die aanmeldings van C. diplodiella is egter wetenskaplik bewys nie en daarom is dit steeds 'n kwarantyn organisme. Hierdie kwarantyn status is egter bevraagteken. Op grond van DNS volgordes van die interne getranskribeerde spasieerder area ("ITS 1", "ITS2"), die 5.8S rRNS geen, die groot ribosomale subeenheid ("LSU") en die verlengingsfaktor 1-α geen ("EF-lα") van die tipe spesies van Pilidiella en Coniella, is Coniella van Pilidiella geskei, met die meerderheid van die taxa wat binne Pilidiella resorteer. Pilidiella word gekarakteriseer deur spesies met hialien tot ligbruin konidia (gem. lengte: breedte > 1.5), in teenstelling met die donkerbruin konidia van Coniella (gem. lengte: breedte ≤ 1.5). Daar is verder bewys dat Pilidiella diplodiella, voorheen C. diplodiella, veroorsakende organisme van witvrot van wingerd, die ouer naam van C. petrakii is. Hierdie swam is teenwoordig in Suid-Afrika en P. diplodiella is dus nie meer van kwarantyn belang nie. Op grond van analises van die histoon (H3) volgordes van spesies in die P. diplodiella spesies kompleks, is P. diplodiella geskei van 'n nuut beskryfde spesie, P. diplodiopsis. 'n Nuwe spesie, P. eucalyptorum, is ook voorgestel vir isolate voorheen beskou as C. fragariae, geassosieer met blaarvlek van Eucalyptus spp. Hierdie spesie het basaal van Pilidiella gegroepeer en mag moontlik nog 'n derde genus binne hierdie kompleks verteenwoordig. Pilidiella destruens is nuut as anamorf van Schizoparme destruens beskryf, wat geassosieer word met loot terugsterwing van Eucalyptus spp. in Hawaii. Die genus Botryosphaeria Ces. & De Not. is bekend as kosmopolitaans met 'n wye gasheerreeks en geografiese verspreiding. Verskeie saprofitiese spesies is aangemeld vanaf wingerd, terwyl ander ernstige patogene van hierdie gasheer is. Laasgenoemde spesies sluit in B. dothidea (Moug.: Fr.) Ces. & De Not., B. parva Pennycook & Samuels, B. obtusa (Schwein.) Shoemaker, B. stevensii Shoemaker, B. lutea A.1.L. Phillips en B. ribis Grossenb. & Duggar. Spesies aangemeld in Suid-Afrika as wingerdpatogene, is B. obtusa, B. dothidea, B. ribis en B. vitis (Schulzer) Sacco In hierdie studie is morfologiese, DNS volgorde data ("ITSl", "ITS2", 5.8S en "EF-Iα") en plantpatologiese data gebruik om II Botryosphaeria spesies, geassosieer met wingerde in Suid-Afrika en verskeie ander werelddele, te onderskei. Botryosphaeria australis, B. lutea, B. obtusa, B. parva, B. rhodina en 'n Diplodia sp. is bevestig van wingerde in Suid-Afrika, terwyl Diplodia porosum, Fusicoccum viticlavatum en F. vitifusiforme as nuwe spesies beskryf is. AIhoewel isolate van B. dothidea en B. stevensii bevestig is van wingerde in Portugal, is geen van hierdie spesies en ook nie B. ribis geïsoleer nie. AIle isolate vanaf wingerd in Portugal, voorheen beskou as B. rib is, is as B. parva op grond van hul "EF-lα" volgordes geïdentifiseer. Uit kunsmatige isolasies gemaak op wingerdlote is die gevolgtrekking gemaak dat B. australis, B. parva, B. ribis en B. stevensii meer virulent is as die ander spesies wat bestudeer is. Die Diplodia sp. versamel vanaf wingerdlote is geïdentifiseer as morfologies eenders, maar filogeneties verskillend van D. sarmentorum, terwyl D. sarmentorum bevestig is as die anamorf van Otthia spiraeae, die tipe spesie van die genus Otthia (Botryosphaeriaceae). 'n Kultuur wat as 0. spiraeae geïdentifiseer is, het binne Botryosphaeria gegroepeer, en word dus as 'n moontlike sinoniem beskou. Hierdie bevindinge bevestig vroeëre voorstelle dat die generiese konsep van Botryosphaeria uitgebrei behoort te word om genera met gesepteerde askospore en Diplodia anamorwe in te sluit. Die genus Phomopsis (Sacc.) Bubak bevat verskeie spesies wat as of plantpatogenies, of saprofities, beskryf is. Tien spesies is bekend op wingerd. Slegs twee is as patogenies bevestig, naamlik P. viticola (Sacc.) Sacc., veroorsakende organisme van loot-en-blaarvlek ("streepvlek") en P. vitimegaspora Kuo & Leu (teleomorf Diaporthe kyushuensis Kajitani & Kanem.), veroorsakende organisme van geswelde arm van wingerd. In 'n vroeëre studie is bevind dat P. amygdali (Delacr.) 1.1. Tuset & M.T. Portilla, 'n bekende patogeen van Prunus sp., moontlik ook 'n patogeen van wingerd mag wees. D. perjuncta Niessl. veroorsaak egter net verbleiking van dormante lote en is dus van min belang as 'n wingerd patogeen. Gedurende die afgelope twee jaar is verskeie Phomopsis isolate van wingerde in die Wes-Kaap provinsie van Suid-Afrika verkry. Isolasies is gemaak van Phomopsis-agtige simptome, snoeiwonde en asimptomatiese kwekeryplante. Die isolate verkry uit hierdie materiaal het groot variasie ten opsigte van morfologie en kultuureienskappe getoon. Vroeëre taksonomiese verhandelings van Phomopsis het spesies-identifikasie op gasheerspesifisiteit, kultuureienskappe en morfologie gebasseer. Onlangse studies het egter getoon dat, weens wye gasheerreekse en morfologiese plastisiteit van somnuge spesies, hierdie eienskappe me meer gebruik kan word om Phomopsis spesies te identifiseer nie. Die gebruik van anamorflteleomorf verwantskappe in die identifikasie van Phomopsis spesies ook onbruikbaar omdat Diaporthe teleomorwe vir slegs ongeveer 20% van die bekende Phomopsis spesies beskryf is. Die huidige studie het dus morfologiese data, DNS volgordes ("ITS 1", 5.8S, "ITS2") en patogenisiteitsdata gekombineer ten einde Phomopsis spp. vanaf wingerd te identifiseer. Vyftien Phomopsis spesies is deur die filogenetiese analise van die interne getranskribeerde spasieerder area ("ITS") volgordes geskei. Diaporthe helianthi, 'n bekende patogeen van sonneblomme, is vir die eerste maal op wingerd aangeteken, terwyl 'n verdere ses, tans onbekende spesies van Phomopsis ook geidentifiseer is. Drie verskillende groepe het isolate bevat wat voorheen as D. perjuncta geidentifiseer is. Gebasseer op studies van tipes, het dit voorgekom dat die naam D. viticola beskikbaar is vir isolate uit Portugal en Duitsland. 'n Nuwe spesie, D. australafricana, is voorgestel vir Suid-Afrikaanse en Australiese isolate wat voorheen behandel is as D. perjuncta of D. viticola. 'n Epitipe monster en kultuur is vir D. perjuncta benoem. Hierdie spesie is van D. viticola en D. australafricana onderskei op grond van morfologie en DNS filogenie. Kunsmatige inokulasies van groen wingerdlote het getoon dat P. amygdali, bekende perske patogeen, en P. viticola die mees virulent was.

Thesis (MScAgric)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Petri disease and esca are devastating grapevine trunk diseases and compromise the sustainability of viticulture world-wide. Despite being extensively studied, knowledge of inoculum sources and mechanisms of spread of the causal pathogens is limited. Arthropods have been suspected to play a role in the spread of Petri disease and esca pathogens. However, little information is known about the extent to which arthropods are associated with these pathogens. This study aimed to determine whether arthropods occurring within or on declining grapevines, are associated with trunk disease pathogens and to identify arthropods associated with pruning wounds. The potential of selected arthropods to act as vectors of trunk disease pathogens was also investigated. Two vineyards exhibiting grapevine trunk disease infections were sampled weekly for two years for collection of arthropods. Arthropods were collected using pruning wound traps, visual searches as well as trunk and cordon traps. Fungal spores from surfaces of arthropods were collected in water. Samples were subjected to nested PCR using primers Pm1/Pm2 and Pch1/Pch2 to verify the presence of Phaeoacremonium spp. and Phaeomoniella chlamydospora, respectively. Water samples were also cultured and grapevine trunk disease pathogens obtained were identified by sequencing the internal transcribed spacers 1 and 2 and the 5.8S rRNA gene or the partial beta-tubulin gene. A total of 10 875 arthropod individuals, belonging to more than 31 families, were collected from declining grapevines. The most abundant arthropods included millipedes, ants, spiders and beetles. Portuguese millipedes and cocktail ants were associated with fresh grapevine pruning wounds. Thirty-three percent of the 5677 water samples analysed, contained propagules of pathogens associated with Petri disease and esca. Of these, 37 % were recovered from millipedes, 22 % from cocktail ants, 15 % from spiders and 10 % from beetles. All the major groups of grapevine trunk diseases were detected on the arthropods. Phaeoacremonium species were detected in 1242 samples while Phaeomoniella chlamydospora was identified from 855 samples. Other fungi isolated included members of the Botryosphaeriaceae, Diatrypaceae and Diaporthales. The potential of grapevine sap as a food source for Portuguese millipedes and cocktail ants was investigated, in vitro. Millipede individuals were offered a choice between water and grapevine sap while ants in nests were presented with grapevine sap, tuna and water and monitored for ingestion of sap. Both taxa preferred grapevine sap over the other food items, indicating close association with pruning wounds. Subsequently, the ability of both taxa to transmit a DsRed-transformed Phaeomoniella chlamydospora isolate to fresh pruning wounds of canes in polystyrene strips, floating in water, and potted vines was tested. Arthropods were exposed to the fungus for 24 hours and transferred to the base of the plants and canes and were removed after three days. Isolations after a month revealed that millipedes and ants were capable of transmitting the fungus onto wounds and cause infection. Millipede faecal pellets were also evaluated as potential sources of inoculum. Millipedes were fed on Phaeomoniella chlamydospora for 24 hours, surface sterilised and allowed to defaecate in sterile Petri dishes overnight. Faecal material was collected, macerated in water and plated onto potato dextrose agar. Propagules of Phaeomoniella chlamydospora survived passage through the gut of millipedes and were passed out in a viable state to form colonies of Phaeomoniella chlamydospora. This study concludes that a wide variety of arthropods can be a source of inoculum of trunk diseases in vineyards. The results of the dissemination trial provides evidence that millipedes and ants are able to disseminate and infect vines with Phaeomoniella chlamydospora. It is therefore, highly likely that other grapevine trunk disease pathogens are transmitted in the same manner. This knowledge highlights the need for control of certain arthropods to be taken into consideration when managing grapevine trunk disease pathogens.
AFRIKAANSE OPSOMMING: Petri siekte en esca is verwoestende wingerd stamsiektes en verhinder die volhoubaarheid van wingerdproduksie wêreldwyd. Hierdie siektes is al intensief bestudeer, maar kennis rakende die inokulum bronne en meganismes van verspreiding van die veroorsakende patogene is beperk. Arthropoda is al vermoed om ‘n rol te speel in die verspreiding van Petri siekte en esca patogene, maar weinig informasie is bekend oor die mate waartoe arthropoda geassosieer is met die patogene. Hierdie studie het ten doel gestel om die arthropoda wat op of in wingerdstokke wat terugsterf voorkom te identifiseer en te bepaal watter van die arthropoda geassosieer is met stamsiekte patogene. Daar is ook ten doel gestel om die arthropoda wat geassosieer is met vars snoeiwonde te identifiseer en ook die moontlike vektor status van die stamsiekte patogene deur arthropoda. Arthropoda is weekliks vir twee jaar gekollekteer vanaf twee wingerde met stamsiekte infeksies. Snoeiwond lokvalle, visuele soektogte en stam- en kordon lokvalle was gebruik om arthropoda te vang. Swamspore van die oppervlak van die arthropoda is afgewas met water. Van hierdie water monsters is gebruik om dubbelvoudige polimerase ketting reaksies (PKR) te doen met die inleiers Pm1/Pm2 en Pch1/Pch2 om vir die teenwoordigheid van Phaeoacremonium spp. en Phaeomoniella chlamydospora onderskeidelik te toets. Die oorblywende water monster is gekweek op medium om die swamme teenwoordig te bepaal. Die wingerd stamsiekte patogene is verder geidentifiseer deur die DNS volgordes te bepaal van die interne getranskribeerde spasies 1 en 2 en die 5.8S rRNS geen of ‘n gedeelte van die beta-tubulien geen. In totaal is 10 875 arthropoda, wat behoort tot 31 families, gekollekteer vanaf wingerde wat terugsterf. Die mees algemene arthropoda was duisendpote, miere, spinnekoppe en kewers. Die Portugese duisendpote en die wipstert mier is geassosieer met vars wingerd snoeiwonde. Van die 5677 water monsters wat geanaliseer is, het 33% propagules van die Petri siekte of esca patogene gehad. Van hierdie was 37 % afkomstig vanaf duisendpote, 22 % van wipstert miere, 15 % van spinnekoppe en 10 % van kewers. Al die hoofgroepe van wingerd stampatogene is opgespoor op die arthropoda. Phaeoacremonium species is opgespoor in 1242 monsters en Phaeomoniella chlamydospora is gevind in 855 monsters. Ander swamme wat ook geisoleer is sluit lede van die Botryosphaeriaceae, Diatrypaceae en Diaporthales in. Die potensiaal van wingerdsap as ‘n bron van voedsel vir Portugese duisendpote en wipstert miere is in vitro ondersoek. Duisendpoot invidue is ‘n keuse gegee tussen water en wingerd sap terwyl mierneste ‘n keuse gehad het tussen water, wingerd sap en tuna. Die duisendpote en miere is gemonitor vir die inname van wingerdsap in die teenwoordigheid van die ander bronne. Beide die duisendpote en miere het wingerdsap verkies wat aandui dat hulle ‘n noue assosiasie met wingerd snoeiwonde het. Vervolgens is beide taksons getoets vir hul vermoë om ‘n DsRooi-getransformeerde Phaeomoniella chlamydospora isolaat te vektor na vars snoeiwonde op lote gemonteer op polistireen stroke wat in water dryf en op wingerd plante in potte. Die duisendpote en miere is blootgestel aan die swam vir 24 uur en oorgedra na die basis van die plante en lote en is weer verwyder na drie dae. Na ‘n maand is isolasies gedoen wat gewys het dat die duisendpote en miere die swam suksesvol kon oordra na die snoeiwonde en infeksie veroorsaak. Duisendpoot uitwerpsels is geëvalueer vir die potensiaal as inokulum bron. Duisendpote het gevoed op Phaeomoniella chlamydospora vir 24 uur, daarna oppervlakkig gesteriliseer en toegelaat om oornag uitwerpsels te maak in steriele Petri bakkies. Uitwerpsels was gekollekteer, fyngemaak in water en op aartappel dekstrose agar uitgeplaat. Propagules van Phaeomoniella chlamydospora het die verteringskanaal van die duisendpote oorleef en het tipiese kolonies op die agar gevorm. Hierdie studie het vasgestel dat ‘n verskeidenheid van arthropoda ‘n bron van inokulum van stamsiektes in wingerd kan wees. Die resultate van die vektor proewe het gewys dat duisendpote en miere die vermoë het om Phaeomoniella chlamydospora te versprei na snoeiwonde wat die swam dan suksesvol geinfekteer het. Dit is daarom hoogs waarskynlik dat van die ander wingerd stamsiekte patogene ook versprei kan word op dieselfde manier. Hierdie kennis demonstreer dat die beheer van spesifieke arthropoda in ag geneem moet word in die bestuur van wingerd stamsiektes.
Winetech, Agricultural Research Council of South Africa and NRF for financial support

Thesis (MScAgric (Plant Pathology))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: A survey was undertaken on apple and pear trees in the Western Cape Province to determine the aetiology of trunk diseases with reference to trunk diseases occurring on grapevine. Grapevine trunk diseases cause the gradual decline and dieback of vines resulting in a decrease in the vine’s capability to carry and ripen fruit. In recent years, viticulture has been expanding into several of the well established pome fruit growing areas. The presence of trunk pathogens in pome fruit orchards may affect the health of the pome fruit trees as well as cause a threat to young vineyards planted in close proximity to these potential sources of viable inoculum. Several genera containing species known to be involved in trunk disease on pome fruit and grapevine were found, including Diplodia, Neofusicoccum, Eutypa, Phaeoacremonium and Phomopsis. Diplodia seriata and D. pyricolum, were isolated along with N. australe and N. vitifusiforme. Four Phaeoacremonium species, P. aleophilum, P. iranianum, P. mortoniae and P. viticola, two Phomopsis species linked to clades identified in former studies as Phomopsis sp. 1 and Phomopsis sp. 7, and Eutypa lata were found. In addition, Paraconiothyrium brasiliense and Pa. variabile, and an unidentified Pyrenochaetalike species were found. Of these the Phaeoacremonium species have not been found on pear wood and it is a first report of P. aleophilum occurring on apple. This is also a first report of the Phomopsis species and Eutypa lata found occurring on pome trees in South Africa Two new coelomycetous fungi were also found including a Diplodia species, Diplodia pyricolum sp. nov., and a new genus, Pyrenochaetoides gen. nov. with the type species, Pyrenochaetoides mali sp. nov., were described from necrotic pear and apple wood. The combined ITS and EF1-α phylogeny supported the new Diplodia species, which is closely related to D. mutila and D. africana. The new species is characterised by conidia that become pigmented and 1-septate within the pycnidium, and that are intermediate in size between the latter two Diplodia species. Phylogenetic inference of the SSU of the unknown coelomycete provided bootstrap support (100%) for a monophyletic clade unrelated to known genera, and basal to Phoma and its relatives. Morphologically the new genus is characterised by pycnidial with elongated necks that lack setae, cylindrical conidiophores that are seldomly branched at the base, and Phoma-like conidia. The phylogenetic results combined with its dissimilarity from genera allied to Phoma, lead to the conclusion that this species represents a new genus. A pathogenicity trial was undertaken to examine the role of these species on apple, pear and grapevine shoots. N. australe caused the longest lesions on grapevine shoots, while Pyrenochaetoides mali, Pa. variabile, D. seriata and P. mortoniae caused lesions that were significantly longer than the control inoculations. On pears, D. pyricolum and N. australe caused the longest lesions, followed by D. seriata and E. lata. On apples, the longest lesions were caused by N. australe and P. iranianum. D. seriata, D. pyricolum, E. lata, N. vitifusiforme, Pa. brasiliense, P. aleophilum and P. mortoniae also caused lesions on apple that were significantly longer than the control. The study demonstrated that close cultivation of grapevine to apple and pear orchards may have inherent risks in terms of the free availability of viable inoculum of trunk disease pathogens.
No Afrikaans abstract available.

In this review, references to the use of microorganisms in the process of plant domestication, genetic improvement, and production of traditional and improved varieties have been identified. The domestication process may have had an adverse impact on the composition and functions of the associated microbiota and the microbiota associated with plants influences multiple regulatory processes of plants that together define their phenotype. According to scientific evidence, to increase agricultural production and the sustainability of production systems, future research should develop breeding methods that optimize the symbiosis between plants and microorganisms, to produce new plant phenotypes that result in the production of enough food to meet the needs of the human population.

People value biodiversity found in tropical rain forests for a variety of utilitarian, aesthetic, moral, ecological, and socioeconomic reasons (Botkin and Talbot, 1992). For instance, traditional medicines derived from plant and animal species found in the tropics provide health services to rural and urban populations; about 25 percent of the pharmaceutical products produced in the United States are associated with plants (WRI et al., 1992). Genetic materials extracted from plant and animal species have contributed to the development of commercial agricultural products (e.g., new varieties of wheat, maize, and rice) that are more resistant to pests and diseases. And nature tourism, often associated with protected wildlife habitats, has become an important source of income, generating about $ 12 billion annually in worldwide earnings (Lindberg, 1991). There are important socioeconomic and political considerations in the valuation of biological resources and the protection of biodiversity. First, the benefits that result from biodiversity have spatial and temporal dimensions. The ecological services linked with biodiversity, such as clean air and water, and the use of genetic material and ingredients extracted from plants, animals, and microorganisms, occur at different places and at different times, often beyond the “economic time scale” of individuals. Second, biodiversity has characteristics of a public good locally arid nationally and may be considered a “global environmental good” in an international context. The benefits of public goods flow to all people regardless of whether they have paid for the good, which means that public goods suffer from the problem of “free riders.” In a national context, economists have long focused attention on the difficulty of financing public goods and have generally concluded that such goods will be underprovided by markets. In the international context, the provision and financing of public goods is even more problematic. These characteristics make management of biodiversity institutionally complex and create problems in defining property rights. Third, conservation of biodiversity can create significant nonuse values. By its very existence, biodiversity can generate economic value without requiring actual use and can provide value by leaving open the option of future use.

We studied the use of the complex microbial preparation (CMP) in 2016-2018 at the experimental field of the Research Institute of Agriculture of Crimea. The soil is southern chernozem. Long-term annual precipitation – 428 mm; long-term annual air temperature – 12 °С. Pisum sativum L. variety – ‘Madonna’. Chemical treating agent Vitavax 200 FF (water suspension concentrate) at the rate of 0.75 l/ha was used in the control variant. Seeds were inoculated with CMP on the day of planting (FSBSI “Research Institute of Agriculture of Crimea” is the owner of CMP). The composition of the studied complex – 1) symbiotic nitrogen fixers; 2) phosphorus mobilizing microorganisms; 3) microorganisms that inhibit the growth and development of phytopathogenic bacteria and fungi. On average, over three years of research, the height of pea plants was the same and amounted to 82.3 cm in the control and 80.7 cm in the experimental variant. The symbiosis of PS and CMP had a significant effect on the number of beans per plant. In the control, 7.6 pieces were formed; under the influence of CMP – 8.6. In our experiments, the grain size was influenced both by the conditions of the growing season in a particular year and the treatment with CMP. The most favorable conditions were in 2016, which contributed to the largest 1000-grain weight (on average 284 g). In extremely arid 2018, the smallest peas were formed (1000-grain weight – 258 g). On average for 2016-2018, the yield in the variant with inoculation was 0.2 t/ha higher. The small Pisum sativum L. yield in 2018 can be explained by the low air humidity and the absence of productive precipitation.