The genetics of resistance of hexaploid wheat to the wheatgrass powdery mildew fungus

Genome ◽  
1990 ◽  
Vol 33 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Y. Tosa ◽  
K. Sakai
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Erysiphe Graminis ◽  
Cultivar Resistance ◽  
Genetics Of Resistance ◽  
Powdery Mildew Fungus ◽  
The Third ◽  
Forma Specialis ◽  
Cultivar Specificity ◽  
Gene For Gene

The avirulence of Erysiphe graminis f.sp. agropyri, Ak-1, on Triticum aestivum 'Norin 4' and 'Norin 10' and T. compactum 'No.44' is conditioned by four genes; three operate singly against each cultivar and one operates against all three cultivars. If the forma specialis – genus specificity follows the gene-for-gene relationship, four major genes should be involved in the resistance of the three cultivars to Ak-1, one carried only by 'Norin 4', one carried only by 'No.44', one carried only by 'Norin 10', and one carried by all three cultivars. The first and second genes were considered to be the previously reported genes Pm10 and Pm11, respectively. The third and fourth genes were successfully detected using F1 hybrid cultures between Ak-1 and E. graminis f.sp. tritici, Tk-1. They were located on chromosomes 6B and 7D and designated Pm14 and Pm15, respectively. These results strongly support the assumption that the forma specialis – genus specificity follows the gene-for-gene relationship. It is, therefore, concluded that this type of specificity belongs to cultivar specificity rather than plant-species specificity and that the resistance to inappropriate formae speciales is essentially cultivar resistance and not nonhost resistance.Key words: powdery mildew, Erysiphe graminis, wheat, wheatgrass, resistance.

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.

Gene-for-gene interactions between the rye mildew fungus and wheat cultivars

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 758-762 ◽  
Author(s):  
Y. Tosa
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Chinese Spring ◽  
Single Gene ◽  
Erysiphe Graminis ◽  
Gene Interactions ◽  
Wheat Cultivars ◽  
Genetic Mechanisms ◽  
Host Parasite ◽  
Gene For Gene

Genetic mechanisms of the incompatibility between Erysiphe graminis f.sp. secalis and wheat cultivars were analyzed using F1 hybrids between E. graminis f.sp. secalis, Sk-1, and f.sp. tritici, Tk-1. The avirulence of Sk-1 on Triticum aestivum 'Norin 4', 'Chinese Spring', and 'Kokeshi-komugi' was controlled by a single gene. The resistance of the three cultivars to Sk-1 was also controlled by a single gene, Pm15, a gene for resistance to E. graminis f.sp. agropyri. Implications of these results were discussed in terms of host–parasite coevolution.Key words: powdery mildew, Erysiphe graminis, resistance, wheat.

scholarly journals Host range and forma specialis of cocksfoot powdery mildew fungus (Erysiphe graminis DC.) found in Japan.

1985 ◽  
Vol 51 (5) ◽  
pp. 613-615 ◽  
Author(s):  
Takashi OKU ◽  
Shuichi YAMASHITA ◽  
Yoji DOI ◽  
Natsuki NISHIHARA
Keyword(s):  
Powdery Mildew ◽  
Host Range ◽  
Erysiphe Graminis ◽  
Powdery Mildew Fungus ◽  
Forma Specialis

Transfer of 35S from wheat to the powdery mildew fungus with compatible and incompatible parasite/host genotypes

1971 ◽  
Vol 49 (2) ◽  
pp. 303-310 ◽  
Author(s):  
R. S. Slesinski ◽  
A. H. Ellingboe
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Primary Infection ◽  
Infection Type ◽  
Radioactive Tracer ◽  
Erysiphe Graminis ◽  
Morphological Development ◽  
Incompatible Interaction ◽  
Powdery Mildew Fungus ◽  
The Relationship

Development of Erysiphe graminis f.sp. tritici on wheat, Triticum aestivum, was studied with compatible and incompatible parasite/host genotypes by measuring the rates of transfer of a radioactive tracer from host to parasite during primary infection. Inoculated wheat plants were fed 35SO4− for various 5-h periods beginning 1 to 21 h after inoculation. Rates of 35S transfer were determined by removing the portion of the fungus on the surface of the leaf with a parlodion film and measuring the amount of radioactivity transferred to the parasite during each 5-h period. Four different parasite/host genotypes which specify incompatibility of the relationship, i.e. P1/Pm1, P2/Pm2, P3a/pm3a, and P4/pm4, differed in the inhibition of 35S transfer according to the time and extent of the incompatible interaction specified by each genotype. With the four genotypes P1/Pm1, P1/pm1, p1/pm1, and p1/Pm1 representing alternative combinations of corresponding genes in the parasite and the host, low rates of transfer were observed with the P1/Pm1 incompatible genotype while similar high rates of transfer were observed with each of the remaining compatible genotypes except p1/Pm1. Rates of 35S transfer were lower for the p1/Pm1 genotype than observed with p1/pm1 even though all three genotypes specify compatibility between parasite and host as evaluated by morphological development of the parasite during primary infection and by infection type at 7 days after inoculation.

Identification of a gene for resistance to wheatgrass powdery mildew fungus in the common wheat cultivar Chinese Spring

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 612-614 ◽  
Author(s):  
Y. Tosa ◽  
H. Tokunaga ◽  
H. Ogura
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Common Wheat ◽  
Chinese Spring ◽  
Wheat Cultivar ◽  
Erysiphe Graminis ◽  
Common Wheat Cultivar ◽  
Powdery Mildew Fungus ◽  
Hybrid Culture ◽  
The Common

A gene for resistance to Erysiphe graminis was detected in Triticum aestivum cv. Chinese Spring, strain Salmon, T. compactum cv. No. 44, and T. spelta var. duhamelianum, using a hybrid culture derived from E. graminis f. sp. agropyri × E. graminis f. sp. tritici. The gene was located on the short arm of chromosome 6B and designated Pm11. Pm11 was considered to be involved in the resistance of wheat to the wheatgrass powdery mildew fungus.Key words: wheat, resistance, powdery mildew, Erysiphe graminis.

Heat-induced resistance in barley to the powdery mildew fungus Erysiphe graminis f.sp. hordei

1995 ◽  
Vol 47 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Patrick Schweizer ◽  
Laurence Vallélian-Bindschedler ◽  
Egon Mösinger
Keyword(s):  
Powdery Mildew ◽  
Induced Resistance ◽  
Erysiphe Graminis ◽  
Powdery Mildew Fungus

Defense reactions of barley cultivars to an inappropriate forma specialis of the powdery mildew fungus of gramineous plants

1984 ◽  
Vol 62 (10) ◽  
pp. 2114-2117 ◽  
Author(s):  
Y. Tosa ◽  
J. Shishiyama
Keyword(s):  
Powdery Mildew ◽  
Colony Growth ◽  
Epidermal Cells ◽  
Colony Development ◽  
Powdery Mildew Fungus ◽  
Barley Cultivars ◽  
Cellular Defense ◽  
Defense Reactions ◽  
Forma Specialis ◽  
Fluorescent Cells

Cellular defense reactions in five barley cultivars against Erysiphe graminis f. sp. tritici were examined in the course of primary and secondary penetrations. In cv. Kairyobozu-mugi, 35% of infection attempts were stopped at fluorescent papillae, and the others (65%) induced fluorescing of epidermal cells, resulting in the failure of the formation of primary haustoria. In the other cultivars ('H.E.S.4', 'Russian No. 12', 'Goseshikoku', and 'Turkey 290') the penetration failures associated with fluorescent papillae reached 50–75%, but the infection attempts that induced the fluorescing of epidermal cells were fewer than 20%. Consequently 10–30% of the germlings that attempted penetration successfully formed normal primary haustoria 48 h after inoculation. In cv. Goseshikoku, cv. Russian No. 12, and cv. H.E.S.4, 50–75% of the epidermal cells that contained the primary haustoria were fluorescent 7 days after inoculation, and colony growth was severely restricted. In cv. Turkey 290 such fluorescent cells scarcely occurred and colonies developed comparatively well. On this cultivar conidia were produced 5–6 days after inoculation, but only in small quantities. This restriction of colony development was mainly attributable to the inhibition of the formation of secondary haustoria by fluorescent papillae. These results indicate that there are differences among barley cultivars in cellular defense reactions against the wheat powdery mildew fungus and suggest that the formation of papillae during the course of primary penetration is not necessarily an essential factor in the resistance of barley to this inappropriate forma specialis.

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