Cochliobolus heterostrophus is a fungal plant pathogen. It can cause southern corn leaf blight in maize. Cochliobolus heterostrophus is found in many tropical regions and in the southern part of the US. Cochliobolus , although not currently the most economically serious disease, can be a very serious crop disease. It was not until the s that C.
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Mutagenesis-based research aimed at obtaining resistance to Helminthosporium maydis , straint T, in maize with Texas male sterile cytoplasm.
Mutagenesis was used on the French line F7T, with Texas male sterile cytoplasm, in order to obtain plants resistant to Helminthosporium maydis. The M 3 seedlings were screened for resistance either by using a fungus culture filtrate or through contamination with the fungus itself. In the first tests, carried out after the seeds had been treated with an aqueous solution of EMS, a number of families exhibiting original types of resistance to Helminthosporium maydis , strain T, were isolated.
Directory of Open Access Journals Sweden. Helminthosporium oryzae is a rice pathogen. Due to its variability in pathogenicity, the possibility of this fungus Infecting other grasses was investigated. The capacity of this pathogen was demonstrated to be able to infect oat, sugar-cane, rye, sorghum, wheat, Brachiaria decumbens and Panicum maximum through artificial inoculations.
Therefore, those plant species can be considered potencial hosts for the fungus in nature. Cloning, sequencing and expression of a xylanase gene from the maize pathogen Helminthosporium turcicum.
A gene encoding an endoxylanase from the phytopathogenic fungus Helminthosporium turcicum Pass. The entire nucleotide sequence of a bp genomic fragment containing an endoxylanase gene was determined.
The xylanase gene of bp, interrupted by two introns of 52 and The role of repellents and hydrophobins in Ustilago maydis. Ustilago maydis is an important model organism to study fungal pathogenicity. In the latter form this fungus infects maize. In my Thesis the expression and function of hydrophobins and repellents of U. Hydrophobins are produced by. Potential of Trichoderma species on Helminthosporium causing leaf spot on cane palm, Chrysalidocarpus lutescens.
The cane palm, Chrysalidocarpus lutescens is one among the plant material of the export industries in Sri Lanka. The export quality of C. Widespread occurrence of the leaf spot affected the cane palm production and succumb it to a huge setback in the floriculture industry in Sri Lanka. Being an export industry eco-friendly means of disease control was the prime focus for a better management of such vulnerable disease. Trichoderma is a potential bio agent, which has definite role in suppressing the inoculum of Helminthosporium sp.
This study aims to evaluate the efficacy of Trichoderma species to control naturally established leaf spot in cane palm under field conditions. Three isolates of T. All the Trichoderma species performed significantly in reducing the disease incidence. The colour of the leaves regained due to the application of Trichoderma sp. The results revealed that leaf spot incidence was lowered significantly in cane palms treated with Trichoderma species followed by treatment with combination of Trichoderma sp.
Mixing of Trichoderma species with fungicide did not exhibit any additive effect. The combination of different species of Trichoderma would target species of Helminthosporium that exist as a complex group under field conditions. The results also proved that the existence of heterogeneity in Helminthosporium that could be tackled and effectively controlled by a combination of different species of the bio. Interaction between Pyricularia oryzae, four Helminthosporium species and Curvularia lunata in rice leaves.
Full Text Available The interaction between six fungal parasites of rice: Pyricularia oryzae, Helminthosporium oryzae, H. Each fungus was inoculated alone or in combination with one of the other five fungi in various proportions into rice plants under experimental conditions. Leaves developing lesions were harvested and incubated in a moist chamber.
The yield of each fungus was its conidial production on the rice leaves. The artificial inoculations indicated that interactions between the pathogens in the mixture could be beneficial, antagonistic, or null.
Interspecific interaction i. The relative yield total RYT lines were significantly lower than the expected value, which is 1. The RYT lines were concave upward, revealing a beneficial effect of one or both pathogens on the other, when H.
A null effect between fungi occurred in four combinations H. Thus, the de Wit replacement series technique indicated that it was possible to quantify the interaction between all the pathogenic fungi tested. RNA polymerase activity of Ustilago maydis virus. Ustilago maydis virus has an RNA polymerase enzyme which is associated with virion capsids.
The dsRNA was determined by characteristic mobilities in gel electrophoresis, lack of sensitivity to RNase, and specific hybridization tests. The following observations indicates that transcription occurs by strand displacement; 1 Only the positive strand of M2 dsRNA was labeled by the in vitro reaction. The transcription products of three UmV strains were compared, and the overall pattern of transcription was very similar among them. Microcycle Conidiation in Cercospora zeae- maydis. On nutrient-deficient substrates, but not on water on the leaf surface, conidia germinate and develop secondary conidia on conidiophores produced from germ tubes or conidial cells.
A population of conidia increases its numbers more than twofold by 2 days on the surface of a water droplet and by fourfold on trichomes. This microcycle conidiation is suppressed by hydrogen peroxide and ammonium compounds but not by nitrate compounds, amino acids, or simple sugars. Microcycle conidiation is sensitive to alpha-amanitin and cycloheximide, suggesting that new RNA and proteins must be synthesized.
Upon transfer from a humid to a dry atmosphere, secondary conidia and conidiophores dehydrate and collapse. Mature, dehydrated, secondary conidia are liberated by wind speeds approximately one-third those required to liberate hydrated conidia.
The dispersed secondary conidia can rehydrate and germinate normally. Because this microcycle conidiation occurs at the expense of endogenous reserves, the ability to produce secondary conidia is lost after four successive cycles without a period of growth on nutrient media.
This alternative method of maintaining inoculum potential during periods of fluctuating relative humidity may have epidemiological consequences when primary conidia fail to infect.
Biomass pretreatment affects Ustilago maydis in producing itaconic acid. Full Text Available Abstract Background In the last years, the biotechnological production of platform chemicals for fuel components has become a major focus of interest. Although ligno-cellulosic material is considered as suitable feedstock, the almost inevitable pretreatment of this recalcitrant material may interfere with the subsequent fermentation steps. In this study, the fungus Ustilago maydis was used to produce itaconic acid as platform chemical for the synthesis of potential biofuels such as 3-methyltetrahydrofuran.
No studies, however, have investigated how pretreatment of ligno-cellulosic biomass precisely influences the subsequent fermentation by U. Thus, this current study aims to first characterize U. Cellulose enzymatically hydrolysed in seawater and salt-assisted organic-acid catalysed cellulose were investigated as substrates.
Lastly, hydrolysed hemicellulose from fractionated beech wood was applied as substrate. Results U. Nitrogen limitation was shown to be a crucial condition for the production of itaconic acid. Performing experiments that simulated influences of possible pretreatment methods, U. The production of itaconic acid was achieved on pretreated cellulose in seawater and on the hydrolysed hemicellulosic fraction of pretreated beech wood.
Conclusion The fungus U. Moreover, U. Sienten Phyllachora maydis Maubl. Maissi Zea mays L. The fungus Ustilago maydis is a biotrophic pathogen parasitizing on maize. The most prominent symptoms of the disease are large tumors in which fungal proliferation and spore differentiation occur. In this study, we have analyzed early and late tumor stages by confocal microscopy.
We show that. We characterized isolates of C. The four AFLP primer-pair combinations generated 68 bands, 25 of which were polymorphic, resulting in 52 clonal haplotypes that clustered the isolates into four phylogenetic lineages.
Three lineages were found in both the Nile River Delta and southern Egypt. Lineage IV, the most diverse group 20 haplotypes , was recovered only from governates in the Nile River Delta. Under field conditions in Egypt, there is no evidence that C. The nonuniform geographic distribution of the pathogen lineages within the country could be due to differences in climate or in the farming system, because host material differs in susceptibility and C.
Plant surface cues prime Ustilago maydis for biotrophic development. Full Text Available Infection-related development of phytopathogenic fungi is initiated by sensing and responding to plant surface cues.
This response can result in the formation of specialized infection structures, so-called appressoria. To unravel the program inducing filaments and appressoria in the biotrophic smut fungus Ustilago maydis , we exposed cells to a hydrophobic surface and the cutin monomer hydroxy hexadecanoic acid. Comparisons with the U.
Targeted gene deletion analysis ascribed a role to up-regulated GH51 and GH62 arabinofuranosidases during plant penetration. Our data also demonstrate specific effects on two transcription factors that redirect the transcriptional regulatory network towards appressorium formation and plant penetration.
This shows that plant surface cues prime U. Cephalosporium maydis is a distinct species in the Gaeumannomyces-Harpophora species complex. Cephalosporium maydis is an important plant pathogen whose phylogenetic position relative to other fungi has not been established clearly. We compared strains of C.
Oligonucleotide primers for H. These diagnostic PCR primers will aid the detection of H. Identification of O-mannosylated virulence factors in Ustilago maydis. Full Text Available The O-mannosyltransferase Pmt4 has emerged as crucial for fungal virulence in the animal pathogens Candida albicans or Cryptococcus neoformans as well as in the phytopathogenic fungus Ustilago maydis.
Canadian Journal of Botany
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Helminthosporium maydis seedling blight of Popcorn.
Mutagenesis-based research aimed at obtaining resistance to Helminthosporium maydis , straint T, in maize with Texas male sterile cytoplasm. Mutagenesis was used on the French line F7T, with Texas male sterile cytoplasm, in order to obtain plants resistant to Helminthosporium maydis. The M 3 seedlings were screened for resistance either by using a fungus culture filtrate or through contamination with the fungus itself. In the first tests, carried out after the seeds had been treated with an aqueous solution of EMS, a number of families exhibiting original types of resistance to Helminthosporium maydis , strain T, were isolated.
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