小麦抗条锈基因Yr17的新SCAR标记的建立与应用

Exploitation and Application of a New SCAR Marker Linked to Strip Rust Resistance Gene Yr17 in Wheat

为深入了解四川小麦新品种(系)中抗条锈病基因的组成,并为开展分子标记辅助育种提供依据,以小麦抗条锈病基因Yr17的近等基因系以及抗条锈病品系L15与感条锈病材料SY95-71的杂交F2代群体为材料,采用集群分离分析法(BSA)结合SSR分子标记进行分析,发现1条由引物Xgwm415扩增的与抗条锈基因Yr17连锁的特异带。对该特异带克隆测序发现,该序列长390 bp,与栽培大麦中的一个序列表达标签(EST)有90%的相似性,与水稻基因组中的一个"核苷酸结合位点(NBS)-富亮氨酸重复(LRR)"型抗病基因的编码区有70%的相似性。根据该序列设计特异引物,建立SCAR标记,命名为SC-372。利用SC-372对54个四川省近年育成的小麦品种(系)进行检测,发现在15个抗病品种(系)中能特异扩增。进一步利用SC-372及前人报道的Yr17连锁标记VENTRUP/LN2对Yr17近等基因系及偏凸山羊草进行扩增比较发现,本实验建立的SCAR标记对小麦背景中的Yr17基因有更好的检测效率。因此可将SC-372用于分子标记聚合小麦抗条锈病基因的育种实践中。

To further clarify the composition of stripe rust resistance gene in the newly developed wheat cultivars （lines） of Sichuan and establish molecular marker-assisted breeding system for rust resistance, the Thatcher Yr17 near isogeneic lines （NILs） and a F2 population derived from a cross between developed resistant line 1.15 and susceptible line SY95-71 were used to screen the SSR markers by bulked segregation analysis （BSA）. A PCR product amplified by Xgwm415 was linked to resistance gene to strip rust resistance gene Yr17. The 390bp sequence of the PCR fragment had 900% identity to one EST of barley and 70% identity to the CDS of a NBS-LRR disease resistance protein in rice. Basing on this sequence, a pair of sequence-characterized amplified region （SCAR） primers were designed, and the SCAR marker, named SC- 372, was able to target 15 resistant cultivars （lines） in all 54 wheat cultivars of newly developed in Sichuan Province. Compared with the amplification of marker VENTRUP/LN2 linked to Yr17, the SC-372 marker showed a higher detection efficierlcy to Yr17 when a set of NILs and Aegilops ventricosa were amplified. It was therefore to conclude that the new SCAR marker for Yr17 gene and the identified resistant lines could be used in wheat breeding for stripe rust resistance.