小麦种质CH7015中抗白粉病基因的SSR定位

Mapping of Resistance Gene to Powdery Mildew in Wheat Cultivar CH7015 Using SSR Markers

为了明确小麦与八倍体小偃麦远缘杂交培育的小麦新种质CH7015中抗白粉病基因的来源及其在染色体上的具体位置。将CH7015与感病品种台长29杂交,对其F1、BC1、F2群体接种白粉病,进行抗病性鉴定和抗感杂交后代的遗传分析,选取分布于小麦21对染色体上的825对SSR引物,采用群体分离分析法(BSA)对台长29×CH7015的F2群体进行标记筛选。结果显示,CH7015抗性受1对显性核基因控制,其抗白粉病基因PmCH7015可能来源于中间偃麦草。通过抗感基因池和群体筛选,获得5个连锁标记,分别为:Xwmc657、Xgpw2328、Xwmc68、Xgpw4079和Xgpw7272。其中,Xwmc68和Xgpw4079位于PmCH7015两侧,遗传距离分别为8.2,1.4 cM。中国春缺体-四体和双端体的验证结果将抗病基因定位于小麦4B染色体的短臂上(4BS)。综上所述,由于小麦4BS染色体上尚无有关抗白粉病基因的报道,因此,推测PmCH7015是一个新发现的抗白粉病基因位点,其抗性可能来源于中间偃麦草。

In order to disclose the genetic mechanisms behind this resistance and identify the powdery mildew resistance gene in CH7015, a new wheat breeding line derived from five hybrids of common wheat crossed with wheat-Thi. intermedium partial amphidiploids,the CH7015 was crossed with Taichang 29 and developed segregating populations F1, BC1, F2 generations. Using 825 pairs SSR primers distributed on 21 pairs of chromosome of common wheat to analysis the F2 populations of Taichang 29 × CH7015. The results of genetic analysis showed that the resistance gene to powdery mildew in CH7015 is a single dominant gene tentatively named pmCH7015, which may be derived from Thi. intermedium. Five SSR markers, i.e., Xwmc657,Xgpw2328,Xwmc68,Xgpw4079 and Xgpw7272, were screened for linking with PmCH7015. And the genetic distances of PmCH7015 with the flanking markers were 8.2 cM to Xwmc68 and 1.4 cM to Xgpw4079. Chinese Spring ditelosomic and nulli-tetrasomic lines were used to locate the gene of PmCH7015 on wheat chromosome 4 BS. Since no related report for Bgt resistance gene in 4 BS of wheat, so far, the results of the study indicated that PmCH7015 is a novel Bgt resistance gene which probably derived from Thi. intermedium.