scholarly journals At Least Five Major Genes Are Involved in the Avirulence of an Eleusine Isolate of Pyricularia oryzae on Common Wheat

2020 ◽  
Vol 110 (2) ◽  
pp. 465-471 ◽  
Author(s):  
Soichiro Asuke ◽  
Shuko Nishimi ◽  
Yukio Tosa
Keyword(s):  
Molecular Markers ◽  
Common Wheat ◽  
Finger Millet ◽  
Segregation Ratio ◽  
Pyricularia Oryzae ◽  
Complementation Test ◽  
Wheat Cultivars ◽  
Avirulence Genes ◽  
The Third ◽  
Genetic Mechanisms

Pyricularia oryzae is composed of pathotypes that show host specificity at the plant genus level. To elucidate the genetic mechanisms of the incompatibility between the Eleusine pathotype (pathogenic on finger millet) and common wheat, an Eleusine isolate (MZ5-1-6) was crossed with a Triticum isolate (Br48) pathogenic on wheat, and resulting F1 cultures were sprayed onto common wheat cultivars Hope, Norin 4 (N4), and Chinese Spring (CS). On Hope, avirulent and virulent cultures segregated in a 3:1 ratio, suggesting that two avirulence genes are involved. They were tentatively designated as eA1 and eA2. On N4 and CS, the segregation ratio was not significantly deviated from the 7:1, 15:1, or 31:1 ratios, suggesting that three or more genes are involved. A comparative analysis of the segregation patterns suggested that two of these genes were eA1 and eA2. A complementation test indicated that the third gene (tentatively designated as eA3) was the Ao9 type of the PWT3 gene controlling the avirulence of Avena and Lolium isolates on wheat. The fourth gene (tentatively designated as eA4) was detected by backcrossing 200R72, an F1 culture lacking eA1, eA2, and eA3, with Br48. Comparative analyses of phenotypes and the presence and/or absence of molecular markers in the F1 population revealed that some cultures were avirulent on N4/CS in spite of lacking eA1, eA2, eA3, and eA4, indicating the presence of the fifth gene (tentatively designated as eA5). Taken together, we conclude that at least five avirulence genes are involved in the incompatibility between MZ5-1-6 and N4/CS.

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.

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 Phytochemical Profile and Nutraceutical Value of Old and Modern Common Wheat Cultivars

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e45997 ◽  
Author(s):  
Emanuela Leoncini ◽  
Cecilia Prata ◽  
Marco Malaguti ◽  
Ilaria Marotti ◽  
Antonio Segura-Carretero ◽  
...  
Keyword(s):  
Common Wheat ◽  
Wheat Cultivars ◽  
Phytochemical Profile

scholarly journals Grain yield and competitive ability against weeds in modern and heritage common wheat cultivars are differently influenced by sowing density

2017 ◽  
Vol 11 ◽  
Author(s):  
Mariateresa Lazzaro ◽  
Ambrogio Costanzo ◽  
Dalia Hosam Farag ◽  
Paolo Bàrberi
Keyword(s):  
Grain Yield ◽  
Common Wheat ◽  
Weed Suppression ◽  
Strong Impact ◽  
Wheat Cultivars ◽  
Modern Cultivar ◽  
Weed Biomass ◽  
Growing Seasons ◽  
Viable Seeds ◽  
Crop Stand

Sowing density can have a strong impact on crop stand development during wheat growing cycle. In organic and low-input agriculture, and therefore with minimum or nil use of chemical herbicides, increased sowing density is expected to affect not only grain yield but also weed suppression. In this study we tested, under Mediterranean conditions, six common wheat cultivars (three modern and three heritage) and two three-component mixtures (arranged by combining the three modern or the three heritage cultivars). The different crop stands were tested at sowing densities of 250 (low) and 400 (high, similar to standard sowing density used by local farmers) viable seeds m-2 for two growing seasons. We did not detect a significant effect of crop stand diversity (single cultivars vs mixtures) on grain yield and weed suppression. Differences were ascribed to type of cultivars used (heritage vs modern). Compared to high sowing density, in modern cultivars grain yield did not decrease significantly with low sowing density whereas in heritage cultivars it increased by 15.6%, possibly also because of 21.5% lower plant lodging. Weed biomass increased with low sowing density both in heritage and modern cultivar crop stand types. However, heritage crop stands had, on average, a lower weed biomass (56%) than modern crop stands. Moreover, weed biomass in heritage crop stands at low density (6.82 ± 1.50 g m-2) was lower than that of modern cultivars at the same sowing density (15.54 ± 3.35 g m-2), confirming the higher suppressive potential of the former. We can conclude that lower sowing density can be advisable when using heritage crop stands as it keeps productivity while decreasing plant lodging and maintaining weeds under control.

The relationship among freezing tolerance, vernalization requirement, Ppd alleles and winter hardiness in European wheat cultivars

2017 ◽  
Vol 155 (9) ◽  
pp. 1353-1370 ◽  
Author(s):  
A. GORASH ◽  
R. ARMONIENĖ ◽  
Ž. LIATUKAS ◽  
G. BRAZAUSKAS
Keyword(s):  
Molecular Markers ◽  
Western Europe ◽  
Complex Trait ◽  
Winter Hardiness ◽  
Photoperiod Sensitivity ◽  
The Other ◽  
Wheat Cultivars ◽  
Crucial Component ◽  
Per Se ◽  
The Relationship

SUMMARYWinter hardiness of wheat is a complex trait involving a system of structural, regulatory and developmental genes, which interact in a complex pathway. The objective of the present work was to study the relationship among the main traits determining the level of adaptation and the possibility for target manipulation of breeding material by using molecular markers and phenological parameters. Wheat cultivars from different ecoclimatic environments of Europe were included for analysis. Gene-specific assay showed that photoperiod sensitivity of the studied cultivars was determined by polymorphism in the Ppd-D1 allele. The study established the relationship among winter hardiness, LT50 (the temperature at which 50% of plants are killed), photoperiod sensitivity, vernalization duration and earliness per se genes in the environment of Lithuania. The cultivars from Northern and Western Europe exhibited stronger requirement for vernalization and photoperiod. Although the group of cultivars from the southern latitudes were characterized by earliness, they possessed a stronger level of LT50. The level of LT50 was found to be the most crucial component of winter hardiness, the other traits served as supplementary components.

scholarly journals Virulence Phenotypes and Molecular Genotypes in Collections of Puccinia triticina from Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 420-424 ◽  
Author(s):  
Paola Mantovani ◽  
Marco Maccaferri ◽  
Roberto Tuberosa ◽  
James Kolmer
Keyword(s):  
Durum Wheat ◽  
Common Wheat ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Leaf Rust Resistance Gene ◽  
The Third ◽  
Virulence Phenotype ◽  
Ssr Loci ◽  
Highly Correlated ◽  
Simple Sequence

Twenty-four isolates of Puccinia triticina from Italy were characterized for virulence to seedlings of 22 common wheat Thatcher isolines, each with a different leaf rust resistance gene, and for molecular genotypes at 15 simple sequence repeat (SSR) loci. The isolates were compared to a set of 13 previously characterized P. triticina isolates from either durum or common wheat. Clustering based on virulence phenotypes and SSR genotypes grouped the Italian P. triticina isolates into three groups. In the first group, the isolates had virulence phenotypes and SSR genotypes that were similar to the isolates collected from durum wheat. Isolates in the second group were unique because they had virulence similar to the isolates from common wheat but were distinct for SSR genotypes compared to the isolates from durum wheat and from common wheat. Isolates in the third group had virulence phenotypes and SSR genotypes closely related to the isolates from common wheat. The isolates were grouped based on the known or assumed host of origin, virulence phenotype, and SSR genotypes. Measures of FST and RST for SSR genotypes, and ΦST for virulence phenotype were significant, which indicated differentiation among the three groups of isolates. Virulence phenotypes and molecular genotypes were highly correlated with r = 0.74.

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.

scholarly journals Genetic mechanisms and distribution characteristics of overpressures in the Paleogene reservoirs of the Bohai Bay Basin, East China

2018 ◽  
Vol 36 (3) ◽  
pp. 388-413 ◽  
Author(s):  
Fanghao Xu ◽  
Jiaju Liang ◽  
Guosheng Xu ◽  
Haifeng Yuan ◽  
Yong Liu
Keyword(s):  
Organic Matter ◽  
Oil And Gas ◽  
Bohai Bay ◽  
Hydrocarbon Generation ◽  
Distribution Characteristics ◽  
Well Drilling ◽  
The Third ◽  
Genetic Mechanisms ◽  
Shahejie Formation ◽  
Tectonic Framework

The Bohai Bay region is a primary accumulation area of oil and gas in offshore China, in which overpressure commonly occurs in the Paleogene strata; the analysis on distribution characteristics and genetic mechanisms of the overpressure would provide geologic evidences for making plans of well drilling and logging as well as oil and gas exploitation; additionally, it could lay the geological foundation for studying how overpressure controlled hydrocarbon accumulation. Based on research, the overpressure of the study area starts from the second member of the Dongying Formation and ends in the third member of the Shahejie Formation. The distribution of overpressure is mainly controlled by the sag–salient tectonic framework within the basin, which means overpressure mainly develops in sags or slopes; however, high areas stay normal pressured. In the study area, pressure develops around Bozhong Sag and in northern Liaodong Bay reaches the peak. The genetic mechanisms of overpressures in the Paleogene reservoirs are mainly disequilibrium compaction, hydrocarbon generation of the organic matter, fluid charging, and transmission or the superimposition of the former two. Different strata have different genetic mechanisms of overpressure. The chief genetic mechanisms for the generation of overpressure of the Dongying Formation are disequilibrium compaction while the genesis of the formation of overpressure in the Shahejie Formation is more complicated in some extent. The first member of the Shahejie Formation dominated by disequilibrium compaction and hydrocarbon generation of the organic matter plays a supplemental role, while the second member of the Shahejie Formation, as the primary reservoir strata, is dominated by fluid charging and transmission, and the third member of the Shahejie Formation is the main source rock interval; its overpressure is closely related to hydrocarbon generation. Each contribution ratio for overpressure forming by different genetic mechanisms has been judged and figured out quantitatively according to geological, geophysical, and geochemical characteristics of the target strata.

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