, a Novel Wheat Blast Resistance Gene Derived from .

Wheat blast, caused by (syn. ) pathotype (MoT), is a devastating disease that can result in up to 100% yield loss in affected fields. To find new resistance genes against wheat blast, we screened 199 accessions of , the D genome progenitor of common wheat (), by seedling inoculation assays with Brazilian MoT isolate Br48 and found 14 resistant accessions.

Identification of in Tetraploid Wheat as a New Blast Resistance Gene with Tolerance to High Temperature.

Wheat blast caused by pathotype has spread to Asia (Bangladesh) and Africa (Zambia) from the endemic region of South America. Wheat varieties with durable resistance are needed, but very limited resistance resources are currently available. After screening tetraploid wheat accessions, we found an exceptional accession St19 (, KU-114).

Loss of , Located on a Supernumerary Chromosome, Is Associated with Parasitic Specialization of on Wheat.

, a blast fungus of gramineous plants, is composed of various host genus-specific pathotypes. The avirulence of an isolate on wheat is conditioned by and . We isolated the third avirulence gene from the isolate and designated it as .

Selective deployment of virulence effectors correlates with host specificity in a fungal plant pathogen.

The hemibiotrophic fungal plant pathogen Colletotrichum orbiculare is predicted to secrete hundreds of effector proteins when the pathogen infects cucurbit crops, such as cucumber and melon, and tobacco (Nicotiana benthamiana), a distantly related Solanaceae species. Here, we report the identification of sets of C. orbiculare effector genes that are differentially required for fungal virulence to two phylogenetically distant host species.

Origin and Dynamics of , a Wheat Gene for Resistance to Nonadapted Pathotypes of .

Avirulence of isolates of on common wheat is conditioned by at least five avirulence genes. One is corresponding to resistance gene located on chromosome 1D. We identified a resistance gene corresponding to a second avirulence gene, , and named it ().

Correlation of Genomic Compartments with Contrastive Modes of Functional Losses of Host Specificity Determinants During Pathotype Differentiation in .

The specificity between pathotypes of and genera of gramineous plants is governed by gene-for-gene interactions. Here, we show that avirulence genes involved in this host specificity have undergone different modes of functional losses dependent on or affected by genomic compartments harboring them. The avirulence of an pathotype on wheat is controlled by five genes, including , which played a key role in the evolution of the pathotype (the wheat blast fungus).

Effectiveness of the Wheat Blast Resistance Gene in Bangladesh Suggested by Distribution of an Allele in the Population.

Wheat blast caused by the pathotype of was first reported in 1985 in Brazil and recently spread to Bangladesh. We tested whether and , recently identified resistance genes, were effective against Bangladeshi isolates of the pathogen. Common wheat accessions carrying alone (IL191) or both and (GR119) were inoculated with Brazilian isolates (Br48, Br5, and Br116.

Evolution of an -Specific Subgroup of Through a Gain of an Avirulence Gene.

isolates (members of the pathotype) of are divided into two subgroups, EC-I and EC-II, differentiated by molecular markers. A multilocus phylogenetic analysis revealed that these subgroups are very close to isolates. EC-II and isolates were exclusively virulent on finger millet and weeping lovegrass, respectively, while EC-I isolates were virulent on both.

A New Resistance Gene in Combination with Rmg8 Confers Strong Resistance Against Triticum Isolates of Pyricularia oryzae in a Common Wheat Landrace.

The wheat blast fungus (Triticum pathotype of Pyricularia oryzae) first arose in Brazil in 1985 and has recently spread to Asia. Resistance genes against this new pathogen are very rare in common wheat populations. We screened 520 local landraces of common wheat collected worldwide with Br48, a Triticum isolate collected in Brazil, and found a highly resistant, unique accession, GR119.

Rmg8 and Rmg7, wheat genes for resistance to the wheat blast fungus, recognize the same avirulence gene AVR-Rmg8.

Rmg8 and Rmg7 are genes for resistance to the wheat blast fungus (Pyricularia oryzae), located on chromosome 2B in hexaploid wheat and chromosome 2A in tetraploid wheat, respectively. AVR-Rmg8, an avirulence gene corresponding to Rmg8, was isolated from a wheat blast isolate through a map-based strategy. The cloned fragment encoded a small protein containing a putative signal peptide.

Rmg8, a New Gene for Resistance to Triticum Isolates of Pyricularia oryzae in Hexaploid Wheat.

Blast, caused by Pyricularia oryzae, is one of the major diseases of wheat in South America. We identified a new gene for resistance to Triticum isolates of P. oryzae in common wheat 'S-615', and designated it "resistance to Magnaporthe grisea 8" (Rmg8).

Identification of a hidden resistance gene in tetraploid wheat using laboratory strains of Pyricularia oryzae produced by backcrossing.

In the process (BC3F1 generation) of backcrossing an Avena isolate of Pyricularia oryzae with a Triticum isolate, color mutants with white mycelia were obtained. These white mutants lacked virulence on all (31/31) hexaploid and most (28/32) tetraploid wheat lines tested. In a BC4F1 population, white and black cultures segregated in a 1:1 ratio, suggesting that the mutant phenotype is controlled by a single gene.

Identification of a novel locus Rmo2 conditioning resistance in barley to host-specific subgroups of Magnaporthe oryzae.

Barley cultivars show various patterns of resistance against isolates of Magnaporthe oryzae and M. grisea. Genetic mechanisms of the resistance of five representative barley cultivars were examined using a highly susceptible barley cultivar, 'Nigrate', as a common parent of genetic crosses.

PWT1, an avirulence gene of Magnaporthe oryzae tightly linked to the rDNA Locus, is recognized by two staple crops, common wheat and barley.

The pathogenicity to wheat (Pwt1) locus conditions host species specificity of Magnaporthe oryzae on wheat. GFSI1-7-2 (Setaria isolate) carries the avirulence allele (PWT1) at this locus while Br48 (Triticum isolate) carries the virulence allele (pwt1). An F(1) culture derived from a cross between GFSI1-7-2 and Br48 was backcrossed with Br48 to produce a tester population in which PWT1 alone segregated.