Identification and genetic mapping of Pm42, a new recessive wheat powdery mildew resistance gene derived from wild emmer (Triticum turgidum var dicoccoides). Theor Appl Genet

Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, People's Republic of China.
Theoretical and Applied Genetics (Impact Factor: 3.79). 05/2009; 119(2):223-30. DOI: 10.1007/s00122-009-1031-4
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Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most important wheat diseases worldwide in areas with cool or maritime climates. Wild emmer (Triticum turgidum var. dicoccoides) is an important potential donor of disease resistances and other traits for common wheat improvement. A powdery mildew resistance gene was transferred from wild emmer accession G-303-1M to susceptible common wheat by crossing and backcrossing, resulting in inbred line P63 (Yanda1817/G-303-1 M//3*Jing411, BC(2)F(6)). Genetic analysis of an F(2) population and the F(2:3) families developed from a cross of P63 and a susceptible common wheat line Xuezao showed that the powdery mildew resistance in P63 was controlled by a single recessive gene. Molecular markers and bulked segregant analysis were used to characterize and map the powdery mildew resistance gene. Nine genomic SSR markers (Xbarc7, Xbarc55, Xgwm148, Xgwm257, Xwmc35, Xwmc154, Xwmc257, Xwmc382, Xwmc477), five AFLP-derived SCAR markers (XcauG3, XcauG6, XcauG10, XcauG20, XcauG22), three EST-STS markers (BQ160080, BQ160588, BF146221) and one RFLP-derived STS marker (Xcau516) were linked to the resistance gene, designated pm42, in P63. pm42 was physically mapped on chromosome 2BS bin 0.75-0.84 using Chinese Spring nullisomic-tetrasomic, ditelosomic and deletion lines, and was estimated to be more than 30 cM proximal to Xcau516, a RFLP-derived STS marker that co-segregated with the wild emmer-derived Pm26 which should be physically located in 2BS distal bin 0.84-1.00. pm42 was highly effective against 18 of 21 differential Chinese isolates of B. graminis f. sp. tritici. The closely linked molecular markers will enable the rapid transfer of pm42 to wheat breeding populations thus adding to their genetic diversity.

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Available from: Zhiyong Liu, Jul 04, 2014
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    • "Pm42 was physically mapped to chromosome bin 2BS4-0.75-0.84 (Hua et al. 2009). Hence, it is likely that PmL962 is different from Pm42 because PmL962 is located in bin 2BS3-0.84-1.00 (Fig. 3a, b). "
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    ABSTRACT: Key message Powdery resistance putatively derived from Thinopyrum intermedium in the wheat line L962 is controlled by a single dominant gene designated PmL962 and mapped to chromosome arm 2BS. Abstract Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease affecting the production of wheat (Triticum aestivum). Powdery mildew resistance was putatively transferred from Thinopyrum intermedium to the common wheat line L962, which conferred resistance to multiple Chinese Bgt isolates. Genetic analysis of the powdery mildew response was conducted by crossing the resistant line L962 with the susceptible line L983. Disease assessments of the F1, F2, and F2:3 populations from the cross L983/L962 indicated that resistance was controlled by a single dominant gene. A total of 373 F2:3 lines and 781 pairs of genomic simple sequence repeat (SSR) primers were employed to determine the chromosomal location of the resistance gene. The gene was linked to four publicly available and recently developed wheat genomic SSR markers and seven EST-STS markers. The resistance gene was mapped to chromosome arm 2BS based on the locations of the linked markers. Pedigree, molecular marker and resistance response data indicated that the powdery mildew resistance gene in L962 is novel. It was temporarily designated PmL962. It is flanked by Xwmc314 and BE443737at genetic distances of 2.09 and 3.74 cM, respectively, and located in a 20.77 cM interval that is co-linear with a 269.4 kb genomic region on chromosome 5 in Brachypodium distachyon and a 223.5 kb genomic region on rice (Oryza sativa) chromosome 4. The markers that are closely linked to this gene have potential applications in marker-assisted breeding.
    Theoretical and Applied Genetics 01/2015; 128(3). DOI:10.1007/s00122-014-2449-x · 3.79 Impact Factor
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    • "Hua et al. 2009 ) , PmG16 ( Ben - David et al . 2010 ) , Ml3D232 ( Zhang et al . "
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    ABSTRACT: Key message: By applying comparative genomics analyses, a high-density genetic linkage map narrowed the powdery mildew resistance gene Pm41 originating from wild emmer in a sub-centimorgan genetic interval. Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, results in large yield losses worldwide. A high-density genetic linkage map of the powdery mildew resistance gene Pm41, originating from wild emmer (Triticum turgidum var. dicoccoides) and previously mapped to the distal region of chromosome 3BL bin 0.63-1.00, was constructed using an F5:6 recombinant inbred line population derived from a cross of durum wheat cultivar Langdon and wild emmer accession IW2. By applying comparative genomics analyses, 19 polymorphic sequence-tagged site markers were developed and integrated into the Pm41 genetic linkage map. Ultimately, Pm41 was mapped in a 0.6 cM genetic interval flanked by markers XWGGC1505 and XWGGC1507, which correspond to 11.7, 19.2, and 24.9 kb orthologous genomic regions in Brachypodium, rice, and sorghum, respectively. The XWGGC1506 marker co-segregated with Pm41 and could be served as a starting point for chromosome landing and map-based cloning as well as marker-assisted selection of Pm41. Detailed comparative genomics analysis of the markers flanking the Pm41 locus in wheat and the putative orthologous genes in Brachypodium, rice, and sorghum suggests that the gene order is highly conserved between rice and sorghum. However, intra-chromosome inversions and re-arrangements are evident in the wheat and Brachypodium genomic regions, and gene duplications are also present in the orthologous genomic regions of Pm41 in wheat, indicating that the Brachypodium gene model can provide more useful information for wheat marker development.
    Theoretical and Applied Genetics 06/2014; 127(8). DOI:10.1007/s00122-014-2336-5 · 3.79 Impact Factor
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    • "Comparison of MlWE4 with other powdery mildew resistance genes derived from wild emmer Wild emmer is an important germplasm for diversified powdery mildew resistance genes. More than 13 alleles in 8 loci conferring powdery mildew resistance have been identified from wild emmer and mapped in 7A, 2B, 3B, 5B, and 6B chromosomes (Reader and Miller 1991; Rong et al. 2000; Liu et al. 2002; Mohler et al. 2005; Ji et al. 2007; Blanco et al. 2008; Hua et al. 2009; Li et al. 2009; Ben-Davis et al. 2010; Zhang et al. 2010; Xie et al. 2011; Liu et al. 2012; Xue et al. 2012). Among them, Pm36, Ml3D232 and PmAs846 were mapped within the same genetic interval of the chromosome arm 5BL (Blanco et al. 2008; Zhang et al. 2010; Xue et al. 2012). "
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    ABSTRACT: Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most devastating wheat diseases. Wild emmer wheat (Triticum turgidum ssp. dicoccoides) is a promising source of disease resistance for wheat. A powdery mildew resistance gene conferring resistance to B. graminis f. sp. tritici isolate E09, originating from wild emmer wheat, has been transferred into the hexaploid wheat line WE4 through crossing and backcrossing. Genetic analyses indicated that the powdery mildew resistance was controlled by a single dominant gene, temporarily designated MlWE4. By mean of comparative genomics and bulked segregant analysis, a genetic linkage map of MlWE4 was constructed, and MlWE4 was mapped on the distal region of chromosome arm 5BL. Comparative genetic linkage maps showed that genes MlWE4, Pm36 and Ml3D232 were co-segregated with markers XBD37670 and XBD37680, indicating they are likely the same gene or alleles in the same locus. The co-segregated markers provide a starting point for chromosome landing and map-based cloning of MlWE4, Pm36 and Ml3D232.
    Journal of Integrative Agriculture 05/2014; 14(4). DOI:10.1016/S2095-3119(14)60774-7 · 0.83 Impact Factor
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