Evidence on wheat for gene-for-gene relationship between formae speciales of Erysiphe graminis and genera of gramineous plants

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 918-924 ◽  
Author(s):  
Y. Tosa
Keyword(s):  
Resistance Gene ◽  
Erysiphe Graminis ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
Major Genes ◽  
Gramineous Plant ◽  
Hybrid Culture ◽  
Series Of Experiments ◽  
The Cross ◽  
Gene For Gene

The avirulence of Erysiphe graminis f.sp. agropyri, Ak-1, on Triticum aestivum 'Norin 4' is conditioned by two major genes. When an F2 population derived from the cross between 'Norin 4' and a susceptible cultivar was inoculated with F1 hybrids between Ak-1 and E. graminis f.sp. tritici, Tk-1, resistant and susceptible seedlings segregated in either a 15:1 or a 3:1 ratio. The F1 cultures producing a 15:1 segregation and those producing a 3:1 segregation occurred in a ratio of 1:2. These results suggested that the resistance of 'Norin 4' to Ak-1 is conditioned by two major genes corresponding to the two avirulence genes. 'Norin 4' carries a resistance gene, Pm10, which operates on an F1 hybrid culture, Gw-34, but not on another F1 culture, Gw-180. Triticum compactum 'No. 44' carries another resistance gene, Pm11, which operates on Gw-180 but not on Gw-34. When these cultivars were inoculated with F2 cultures derived from the cross Gw-34 × Gw-180, avirulent and virulent cultures segregated in a 1:1 ratio. The segregation patterns on the two cultivars were independent. These results indicated that, for each of Pm10 and Pm11, there is one corresponding avirulence gene. These genes were considered to be derived from the wheatgrass mildew fungus, Ak-1. The two series of experiments strongly suggest that the forma specialis – genus specificity in the E. graminis – gramineous plant system follows the gene-for-gene theory.Key words: powdery mildew, Erysiphe graminis, wheat, wheatgrass.

Chromosome landing near avirulence gene vH13 in the Hessian fly

Genome ◽  
2002 ◽  
Vol 45 (5) ◽  
pp. 812-822 ◽  
Author(s):  
Stanley Dean Rider, Jr. ◽  
Weilin Sun ◽  
Roger H Ratcliffe ◽  
Jeffrey J Stuart
Keyword(s):  
Linkage Disequilibrium ◽  
Bulked Segregant Analysis ◽  
Gene Interaction ◽  
Hessian Fly ◽  
Mayetiola Destructor ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
Site Specific ◽  
Triticum Spp ◽  
Gene For Gene

AFLP markers in linkage disequilibrium with vH13, an avirulence gene in the Hessian fly (Mayetiola destructor) that conditions avirulence to resistance gene H13 in wheat (Triticum spp.), were discovered by bulked segregant analysis. Five AFLPs were converted into codominant site-specific markers that genetically mapped within 13 cM of this gene. Flanking markers used as probes positioned vH13 near the telomere of the short arm of Hessian fly chromosome X2. These results suggest that the X-linked avirulence genes vH6, vH9, and vH13 are present on Hessian fly chromosome X2 rather than on chromosome X1 as reported previously. Genetic complementation demonstrated that recessive alleles of vH13 were responsible for the H13-virulence observed in populations derived from four different states in the U.S.A.: Georgia, Maryland, Virginia, and Washington. Results support the hypothesis that a gene-for-gene interaction exists between wheat and Hessian fly.Key words: bulked segregant analysis, gene-for-gene interaction, wheat, Triticum, Mayetiola destructor.

Genetic analysis of the avirulence of wheatgrass powdery mildew fungus on common wheat

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 913-917 ◽  
Author(s):  
Y. Tosa
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Genetic Analysis ◽  
Common Wheat ◽  
Erysiphe Graminis ◽  
Wheat Cultivars ◽  
Avirulence Genes ◽  
Powdery Mildew Fungus ◽  
Major Genes ◽  
Formae Speciales

F1 hybrid cultures between Erysiphe graminis f.sp. agropyri (wheatgrass mildew fungus) and E. graminis f.sp. tritici (wheat mildew fungus) were produced by using a common host of the two formae spéciales. When three common wheat cultivars, Triticum aestivum cv. Norin 4, T. aestivum cv. Norin 10, and T. compactum cv. No. 44, were inoculated with a population of F1 cultures, avirulent and virulent cultures segregated in a 3:1 ratio. This indicated that two major genes are involved in the avirulence of E. graminis f.sp. agropyri, Ak-1, on each of the three cultivars. Further analyses revealed that the three pairs of avirulence genes have one gene in common. On T. aestivum cv. Shin-chunaga, T. aestivum cv. Norin 26, and a strain of T. macha, the F1 population segregated in the same pattern as on T. aestivum cv. Norin 4, indicating that the same pair of avirulence genes is operating on these four cultivars. On T. aestivum cv. Red Egyptian the distribution of F1 phenotypes was continuous, suggesting that no major genes are involved in the avirulence of Ak-1 on this cultivar.Key words: powdery mildew, Erysiphe graminis, avirulence, wheat, wheatgrass.

scholarly journals Standing genetic variation of the AvrPm17 avirulence gene in powdery mildew limits the effectiveness of an introgressed rye resistance gene in wheat

2021 ◽  
Author(s):  
Marion C. Mueller ◽  
Lukas Kunz ◽  
Seraina Schudel ◽  
Sandrine Kammerecker ◽  
Jonatan Isaksson ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Powdery Mildew ◽  
Qtl Mapping ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Resistance Breeding ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
Immune Receptor ◽  
Wheat Powdery Mildew

AbstractIntrogressions of chromosomal segments from related species into wheat are important sources of resistance against fungal diseases. The durability and effectiveness of introgressed resistance genes upon agricultural deployment is highly variable - a phenomenon that remains poorly understood as the corresponding fungal avirulence genes are largely unknown. Until its breakdown, the Pm17 resistance gene introgressed from rye to wheat provided broad resistance against powdery mildew (Blumeria graminis). Here, we used QTL mapping to identify the corresponding wheat mildew avirulence effector AvrPm17. It is encoded by two paralogous genes that exhibit signatures of re-occurring gene conversion events and are members of a mildew sub-lineage specific effector cluster. Extensive haplovariant mining in wheat mildew and related sub-lineages identified several ancient virulent AvrPm17 variants that were present as standing genetic variation in wheat powdery mildew prior to the Pm17 introgression, thereby paving the way for the rapid breakdown of the Pm17 resistance. QTL mapping in mildew identified a second genetic component likely corresponding to an additional resistance gene present on the 1AL.1RS translocation carrying Pm17. This gene remained previously undetected due to suppressed recombination within the introgressed rye chromosomal segment. We conclude that the initial effectiveness of 1AL.1RS was based on simultaneous introgression of two genetically linked resistance genes. Our results demonstrate the relevance of pathogen-based genetic approaches to disentangle complex resistance loci in wheat. We propose that identification and monitoring of avirulence gene diversity in pathogen populations becomes an integral part of introgression breeding to ensure effective and durable resistance in wheat.Significance StatementDomesticated and wild wheat relatives provide an important source of new immune receptors for wheat resistance breeding against fungal pathogens. The durability of these resistance genes is variable and difficult to predict, yet it is crucial for effective resistance breeding. We identified a fungal effector protein recognised by an immune receptor introgressed from rye to wheat. We found that variants of the effector allowing the fungus to overcome the resistance are ancient. They were already present in the wheat powdery mildew gene pool before the introgression of the immune receptor and are therefore responsible for the rapid resistance breakdown. Our study demonstrates that the effort to identify new resistance genes should be accompanied by studies of avirulence genes on the pathogen side.

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

2018 ◽  
Vol 108 (11) ◽  
pp. 1299-1306 ◽  
Author(s):  
Shizhen Wang ◽  
Soichiro Asuke ◽  
Trinh Thi Phuong Vy ◽  
Yoshihiro Inoue ◽  
Izumi Chuma ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Common Wheat ◽  
Resistance Genes ◽  
Pyricularia Oryzae ◽  
Avirulence Gene ◽  
Combined Effects ◽  
Hybrid Culture ◽  
New Gene ◽  
Susceptible Control ◽  
Moderately Resistant

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. When F2 seedlings derived from a cross between GR119 and Chinese Spring (CS, susceptible control) were inoculated with Br48, resistant and susceptible seedlings segregated in a 15:1 ratio, suggesting that GR119 carries two resistance genes. When the F2 seedlings were inoculated with Br48ΔA8 carrying a disrupted allele of AVR-Rmg8 (an avirulence gene corresponding to a previously reported resistance gene, Rmg8), however, the segregation fitted a 3:1 ratio. These results suggest that one of the two genes in GR119 was Rmg8. The other, new gene was tentatively designated as RmgGR119. GR119 was highly resistant to all Triticum isolates tested. Spikes of GR119 were highly resistant to Br48, moderately resistant to Br48ΔA8 and a hybrid culture carrying avr-Rmg8 (nonfunctional allele), and highly resistant to its transformant carrying AVR-Rmg8. The strong resistance of GR119 was attributed to the combined effects of Rmg8 and RmgGR119.

Origin and dynamics of Rwt6, a wheat gene for resistance to non-adapted pathotypes of Pyricularia oryzae

2021 ◽  
Author(s):  
Soichiro Asuke ◽  
Yuta Umehara ◽  
Yoshihiro Inoue ◽  
Trinh Thi Phuong Vy ◽  
Mizuki Iwakawa ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Common Wheat ◽  
Caspian Sea ◽  
Aegilops Tauschii ◽  
Coastal Region ◽  
Pyricularia Oryzae ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
The Caspian Sea ◽  
D Genome

Avirulence of Eleusine isolates of Pyricularia oryzae on common wheat is conditioned by at least five avirulence genes. One is PWT3 corresponding to resistance gene Rwt3 located on chromosome 1D. We identified a resistance gene corresponding to a second avirulence gene, PWT6, and named it Rmg9 (Rwt6). Rwt6 was closely linked to Rwt3. A survey of the population of Aegilops tauschii, the D genome donor to common wheat, revealed that some accessions from the southern coastal region of the Caspian Sea, the birthplace of common wheat, carried both genes. Rwt6 and Rwt3 carriers accounted for 65% and 80%, respectively, of accessions in a common wheat landrace collection. The most likely explanation of our results is that both resistance genes were simultaneously introduced into common wheat at the time of hybridization of Triticum turgidum and Ae. tauschii. However, a prominent difference was recognized in their geographical distributions in modern wheat; Rwt3 and Rwt6 co-occurred at high frequencies in regions to the east of the Caspian Sea, whereas Rwt6 occurred at a lower frequency than Rwt3 in regions to the west. This difference was considered to be associated with range of pathotypes to which these genes were effective. Ae. tauschii accessions carrying Rwt3 and Rwt6 also carried Rwt4, another resistance gene involved in the species specificity. We suggest that the gain of the D genome should have given an adaptive advantage to the genus Triticum by conferring disease resistance.

scholarly journals Identification of a Novel Locus Rmo2 Conditioning Resistance in Barley to Host-Specific Subgroups of Magnaporthe oryzae

2012 ◽  
Vol 102 (7) ◽  
pp. 674-682 ◽  
Author(s):  
Nguyen Thi Thanh Nga ◽  
Yoshihiro Inoue ◽  
Izumi Chuma ◽  
Gang-Su Hyon ◽  
Kazuma Okada ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Molecular Mapping ◽  
The Other ◽  
Avirulence Gene ◽  
Barley Cultivar ◽  
Avirulence Genes ◽  
Genetic Crosses ◽  
Barley Cultivars ◽  
Genetic Mechanisms ◽  
Common Parent

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. The resistance of the five cultivars against Setaria, Oryza, Eleusine, and Triticum isolates of M. oryzae was all attributed to a single locus, designated as Rmo2. Nevertheless, the Rmo2 locus in each cultivar was effective against a different range of isolates. Genetic analyses of pathogenicity suggested that each cultivar carries an allele at the Rmo2 locus that recognizes a different range of avirulence genes. One allele, Rmo2.a, corresponded to PWT1, which conditioned the avirulence of Setaria and Oryza isolates on wheat, in a gene-for-gene manner. The other alleles, Rmo2.b, Rmo2.c, and Rmo2.d, corresponded to more than one avirulence gene. On the other hand, the resistance of those cultivars to another species, M. grisea, was conditioned by another locus, designated as Rmo3. These results suggest that Rmo2 is effective against a broad range of blast isolates but is specific to M. oryzae. Molecular mapping revealed that Rmo2 is located on the 7H chromosome.

Identification and fine mapping of Pi33, the rice resistance gene corresponding to the Magnaporthe grisea avirulence gene ACE1

2003 ◽  
Vol 107 (6) ◽  
pp. 1139-1147 ◽  
Author(s):  
R. Berruyer ◽  
H. Adreit ◽  
J. Milazzo ◽  
S. Gaillard ◽  
A. Berger ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Fine Mapping ◽  
Magnaporthe Grisea ◽  
Avirulence Gene

A Disease Resistance Gene in Arabidopsis with Specificity for Two Different Pathogen Avirulence Genes

1994 ◽  
Vol 6 (7) ◽  
pp. 927
Author(s):  
Sherryl R. Bisgrove ◽  
Michael T. Simonich ◽  
Nadine M. Smith ◽  
Airlie Sattler ◽  
Roger W. Innes
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Disease Resistance Gene ◽  
Avirulence Genes
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