小麦NBS-LRR类抗病基因类似片段分离和定位

Isolation and Mapping of NBS-LRR Resistance Gene Homology Sequences from Wheat

【目的】利用同源序列法分离小麦NBS-LRR类抗病基因类似片段,并验证其与小麦抗条锈病基因Yr26之间的关系。【方法】根据已克隆R(抗病)基因的保守结构域(NBS-LRR)设计简并引物,采用巢式PCR(NestedPCR)技术对小麦Yr26近等基因系材料Nan137的基因组DNA进行扩增;同时利用中国春缺失系对获得的抗病基因类似片段进行染色体定位分析,利用Yr26载体品种92R137和感病品种Avcoet S(AvS)创制的F2:3后代群体验证获得的片段与小麦抗条锈病基因Yr26的关系。【结果】通过巢式PCR方法,获得了4个通读的小麦抗病基因NBS-LRR类抗病基因同源片段R105、R181、R326和R405,长度分别为369、589、528、618 bp;这4个片段均具有典型的NBS-LRR类的保守结构域,其核苷酸相似性为24.35%—38.36%。中国春缺失系定位结果显示片段R405被定位于Yr26所在的小麦缺失系C-1BL-6-0.32区段内,同时通过含196个单株的小群体检测结果表明该片段与Yr26共分离。【结论】从小麦近等基因系材料Nan137中获得了4个RGAs片段,其中片段R405可能是小麦抗条锈病基因Yr26的候选片段,但需进一步验证该候选片段的真实性。

【Objective】The objective of this study is to isolate NBS-LRR class resistance gene homology fragments from wheat using homology-based method,and to validate the relationships with wheat stripe rust resistance gene Yr26.【Method】Primers were designed based on the conserved domains of the cloned plant disease resistance genes,and the nested PCR was used.The fragments were localized by Chinese Spring（CS） deletion lines of chromosome 1B,F2：3 populations derived from susceptible cultivar Avocet S and the lines 92R137 carrying Yr26 were used to evaluate the relationship between the isolated RGAs and Yr26.【Result】Four open-reading resistance gene analogues（RGAs） were obtained,i.e.,R105,R181,R326 and R405.The nucleotide sequences of the four RGAs were 369,589,528 and 618 bp.Homology research showed that the four fragments had typical conserved regions NBS-LRR,and the nucleotide identity of four fragments was from 24.35% to 38.36%.Only R405 was mapped in the deletion bin C-1BL-0.6-0.32 with Chinese Spring deletion lines and was co-segregated with a F2 population of 196 plants.It was initially hypothesized that the R405 might be the candidate sequence of Yr26.【Conclusion】In this study,four resistance homology fragments were obtained in the near isogenic lines（NILs） Nan137.R405 was mapped in the Yr26 region and co-segregated with Yr26,which provides a good prerequisite for further study.