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tA Single Amino Acid Difference Distinguishes Resistant and Susceptible Alleles of the Rice Blast Resistance Gene Pi-ta  

UK PubMed Central (United Kingdom)

The rice blast resistance (R) gene Pi-ta mediates gene-for-gene resistance against strains of the fungus Magnaporthe grisea that express avirulent...Full Text Available

2000-11-01

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Genetic studies of fertility and pathogenicity in Magnaporthe grisea (Pyricularia oryzae)  

Energy Technology Data Exchange (ETDEWEB)

Crosses between field isolates of Magnaporthe grisea (anamorph, Pyricularia oryzae Cav. and Pyricularia grisea) have led to the development of fertile laboratory strains that infect goosegrass and/or weeping lovegrass. These strains may now be utilized in a rigorous genetic analysis of host species specificity and general pathogenicity. Attempts to improve the fertility of rice pathogens for the goal of undertaking a genetic analysis of host cultivar specificity have so far been unsuccessful. Crosses between M. grisea strains that infect rice, goosegrass or weeping lovegrass demonstrate that host species specificity differences between field isolates of this fungus in some cases have a complete genetic basis, and in other cases have a simple genetic basis. Crosses between a field isolate of the pathogen that infects weeping lovegrass and a field isolate that infects goosegrass have resulted in the ...

1984-01-01

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Characterization of the heterokaryotic and vegetative diploid phases of Magnaporthe grisea  

Energy Technology Data Exchange (ETDEWEB)

The heterokaryotic and vegetative diploid phases of Magnaporthe grisea, a fungal pathogen of grasses, have been characterized. Hyphal tip cells and conidia (vegetative spores) taken from these heterokaryons are auxotrophs with phenotypes identical to one or the other of the parents. M. grisea heterokaryons have completely septate hyphae with a single nucleus per cell. Heterokaryons have been utilized for complementation and dominance testing of mutations that affect nutritional characteristics of the fungus. Heterokaryons growing on minimal medium spontaneously give rise to fast-growing sectors that have the genetic properties expected of unstable heterozygous diploids. In fast-growing sectors, most hyphal tip cells are unstable prototrophs. The conidia collected from fast-growing sectors include stable and unstable prototrophs, as well as auxotrophs that exhibit a wide range of phenotypes, including many recombinant ...

1984-01-01

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Survey and analysis of simple sequence repeats in the Laccaria bicolor genome, with development of microsatellite markers  

Energy Technology Data Exchange (ETDEWEB)

It is becoming clear that simple sequence repeats (SSRs) play a significant role in fungal genome organization, and they are a large source of genetic markers for population genetics and meiotic maps. We identified SSRs in the Laccaria bicolor genome by in silico survey and analyzed their distribution in the different genomic regions. We also compared the abundance and distribution of SSRs in L. bicolor with those of the following fungal genomes: Phanerochaete chrysosporium, Coprinopsis cinerea, Ustilago maydis, Cryptococcus neoformans, Aspergillus nidulans, Magnaporthe grisea, Neurospora crassa and Saccharomyces cerevisiae. Using the MISA computer program, we detected 277,062 SSRs in the L. bicolor genome representing 8% of the assembled genomic sequence. Among the analyzed basidiomycetes, L. bicolor exhibited the highest SSR density although no correlation between relative abundance and the genome sizes was observed. In most genomes the short ...

2011-01-01

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Structures of trihydroxynaphthalene reductase-fungicide complexes: implications for structure-based design and catalysis  

Energy Technology Data Exchange (ETDEWEB)

Trihydroxynaphthalene reductase catalyzes two intermediate steps in the fungal melanin biosynthetic pathway. The enzyme, a typical short-chain dehydrogenase, is the biochemical target of three commercial fungicides. The fungicides bind preferentially to the NADPH form of the enzyme. Three X-ray structures of the Magnaporthe grisea enzyme complexed with NADPH and two commercial and one experimental fungicide were determined at 1.7 {angstrom} (pyroquilon), 2.0 {angstrom} (2,3-dihydro-4-nitro-1H-inden-1-one, 1), and 2.1 {angstrom} (phthalide) resolutions. The chemically distinct inhibitors occupy similar space within the enzyme's active site. The three inhibitors share hydrogen bonds with the side chain hydroxyls of Ser-164 and Tyr-178 via a carbonyl oxygen (pyroquilon and 1) or via a carbonyl oxygen and a ring oxygen (phthalide). Active site residues occupy similar positions among the three structures. A buried water molecule that is ...

2010-03-08

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Structural definition of the active site and catalytic mechanism of 3,4-dihydroxy-2-butanone 4-phosphate synthase  

Energy Technology Data Exchange (ETDEWEB)

X-ray crystal structures of L-3,4-dihydroxy-2-butanone-4-phosphate synthase from Magnaporthe grisea are reported for the E-SO{sub 4}{sup 2-}, E-{sub 4}{sup 2-}-Mg{sup 2+}, E-SO{sub 4}{sup 2-}-Mn{sup 2+}, E-SO{sub 4}{sup 2-}-Mn{sup 2+}-glycerol, and E-SO{sub 4}{sup 2-}-Zn{sup 2+} complexes with resolutions that extend to 1.55, 0.98, 1.60, 1.16, and 1.00 {angstrom}, respectively. Active-site residues of the homodimer are fully defined. The structures were used to model the substrate ribulose 5-phosphate in the active site with the phosphate group anchored at the sulfate site and the placement of the ribulose group guided by the glycerol site. The model includes two Mg{sup 2+} cations that bind to the oxygen substituents of the C2, C3, C4, and phosphate groups of the substrate, the side chains of Glu37 and His153, and water molecules. The position of the metal cofactors and the substrate's phosphate group are further stabilized by an ...

2010-03-08

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Primary study on lesion mimic mutants of rice (oryza sativa L.)  

International Nuclear Information System (INIS)

Nineteen lesion mimic mutants (xsl1-19) of japonica rice Xiushui11 were obtained by ?-rays irradiation treatment. All mutants belonged to whole life lesion mimic. Lesion mimic of mutants didn't largen after tillering stage, leaves didn't wither, and no effect on the plants exsert spikes and seed. When the highest temperature in day exceeded 32 degree C in seedling stage, lesion mimic of all mutant expect xsl19 disappeared. Under 32 degree C, lesion mimic would appear gradually, and symptoms weren't inhibited by high temperature after 5 leaf stage. The plant heights of all lesion mimic mutants were 47.56-63.54 cm in the tillering stage, and that of CK was 83.75 cm; but the dwarf phenomenon of mutants only appeared before tillering stage, and didn't affect plant heights finally; the heading dates of mutants were the same to the CK, the ear length of all mutants were 9.43-15.19 cm, and that of CK was 16.41 cm; the total grain quantity per spike of all mutants were 88.17-165.33, and those ...

2007-08-01

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Genetic Stability of Magnaporthe oryzae during Successive Passages through Rice Plants and on Artificial Medium  

KoreaScience (Korea)

Full Text Available

2010-12-01

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Rice RING protein OsBBI1 with E3 ligase activity confers broad-spectrum resistance against Magnaporthe oryzae by modifying the cell wall defence  

British Library Electronic Table of Contents (United Kingdom)

Emerging evidence suggests that E3 ligases play critical roles in diverse biological processes, including innate immune responses in plants. However, the mechanism of the E3 ligase involvement in plant innate immunity is unclear. We report that a rice gene, OsBBI1, encoding a RING finger protein with E3 ligase activity, mediates broad-spectrum disease resistance. The expression of OsBBI1 was induced by rice blast fungus Magnaporthe oryzae, as well as chemical inducers, benzothiadiazole and salicylic acid. Biochemical analysis revealed that OsBBI1 protein possesses E3 ubiquitin ligase activity in vitro. Genetic analysis revealed that the loss of OsBBI1 function in a Tos17-insertion line increased susceptibility, while the overexpression of OsBBI1 in transgenic plants conferred enhanced resi...

2011-01-01

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Response of the panicles exserted from the caulis and from various effective tillers at four stages of panicle development to neck blast in rice  

British Library Electronic Table of Contents (United Kingdom)

The rice japonica variety Nipponbare and the indica variety 93-11, the genomic DNA sequences of which are known, were used to analyze the response of the panicles exserted from the caulis and from various effective tillers at four stages of panicle development to neck blast. Disease incidence in the necks (DIN), disease incidence in the rachis nodes (DIRN), lesion length in the necks (LLN), and number of conidia in the necks (NCN) were measured after inoculating the panicles in vitro of two rice varieties with Magnaporthe oryzae. Both Nipponbare and 93-11 were susceptible, DIN and DIRN of all panicles being 100% in both the varieties except DIRN in several panicles at stage 1 (the panicle fully exserted) in Nipponbare. Both LLN and NCN of panicles decreased as the panicles continued to dev...

2011-01-01