普通小麦DH155抗白粉病基因的分子作图及应用分子标记辅助选择将其转移

普通小麦品系DH155对白粉病菌表现高抗。为明确DH155所携带抗白粉病基因的遗传方式及与抗病基因连锁SSR标记,利用DH155与高感小麦品系SN2890杂交获得的F2和F2:3群体进行接种鉴定和遗传分析,发现DH155对白粉菌菌株E09的抗性受1对显性基因控制,暂命名为Ml DH155。BSA和分子标记分析结果显示,Ml DH155与SSR标记Xcfd81和Xcfd18连锁。利用已发表的中国春和粗山羊草D基因组序列开发新标记,进一步将Ml DH155定位于标记Xsdau K525和Xsdau K527之间,其遗传距离分别为0.2 c M和0.8 c M。将DH155与感白粉病优良品系HB133-4和旱10杂交,在F2~F4代,结合优良农艺性状选择、分子标记辅助选择和抗白粉病鉴定,获得3个高抗白粉病且农艺性状优异的株系(SDAU2100、SDAU2101和SDAU2102)。利用14个白粉菌菌株对DH155进行苗期接种鉴定表明,DH155对13个菌株表现抗病反应型。这些菌株对DH155的毒力谱与已知抗白粉病基因Pm2相似,但DH155对Bg78-3和Bg44-5菌株的反应型与携带Pm2的Ulka/8*Cc不同。结合本试验结果和Pm2基因的相关报道,推测Ml DH155可能是Pm2或其等位基因。

Molecular Mapping of Powdery Mildew Resistance Gene MlDH155 in Hexaploid Wheat DH155 and Its Transfer by Marker Assisted Selection

Hexaploid wheat (Triticum aestivum L.) line DH155 is highly resistant to wheat powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt). To identify the Bgt resistance gene(s) in DH155, we developed an F₂ population and its derived F_2:3 families by crossing the resistant line DH155 with the susceptible line SN2890. The segregation ratios indicated that the seedling resistance to Bgt E09 in DH155 was controlled by a single dominant gene, which was tentatively designated MlDH155. By bulked segregation analysis, two codominant SSR markers, Xcfd81 and Xcfd18, were identified to be linked to MlDH155. To identify the closely linked markers to the targeted gene, we developed five new molecular markers based on the published D genome sequences of Chinese Spring and Aegilops tauschii, which permitted mapping of MlDH155 within an interval of 1.0 cM, flanked by XsdauK525 and XsdauK527. The Pm resistant line DH155 was crossed with two elite wheat lines (HB133-4 and Han 10) but susceptible to powdery mildew. Subsequently, two powdery mildew resistant lines with the genetic background of HB133-4 and one resistant line with Han 10 background were developed by genotypic and phenotypic selection, which were designated by the name of SDAU2100, SDAU2101 and SDAU2102, respectively. Among the 14 Bgt isolates tested at the seedling stage, DH155 was resistant to 13 and susceptible to 1 isolates. The virulence pattern of these Bgt isolates on DH155 was similar to that of the known powdery mildew resistance gene Pm2, but the reactions of DH155 to two Bgt isolates differed from those of Ulka/8*Cc carrying Pm2. Compared to previous studies about Pm2, MlDH155 was most likely to be either the same as or an allele of Pm2.