小麦抗白粉病基因Pm43定位区段内RGA分析

利用普通小麦测序草图可从基因组范围内对小麦单条染色体上的某个区段进行分析。Pm43是作物遗传与分子改良山西省重点实验室在小麦2D染色体长臂上定位的一个抗白粉病基因。利用信息学方法分析Pm43所在物理图谱、遗传图谱和基因组图谱上的位置,可为其精细定位乃至候选基因的确定提供参考。试验采用Pm43两侧标记序列进行比对,将Pm43定位于染色体C-2DL3-0.49区间的79~99 c M内,所在基因组区段为2DL_9835990~2DL_9823315。利用目前已克隆小麦抗病基因的保守基序作为探针,从目标区段内检索出89条包含抗病基因类似物(Resistance gene analogues,RGA)序列的scaffold,其中,36条scaffold被诊断出含有SSR位点,之后针对SSR位点开发分子标记。利用携带有Pm43的普通小麦材料CH5025、感白粉病材料台长29以及CH5025×台长29的F2作图群体的抗感池DNA,对开发的SSR标记进行连锁性检测,共筛选出4个多态性标记,从而将目标区段进一步确定在标记PK_9908430和NBS_9908778之间。最后经聚类分析,筛选出与已克隆Pm基因同源性较高的1个PK序列和1个NBS序列,且在粗山羊草2D染色体和水稻第4染色体中均存在与这2个序列同源的RGA表达序列。

Analysis of Resistance Gene Analogues from the Section of Mildew Powdery Resistance Gene Pm43 in Wheat

Draft sequencing data of common wheat can be used to analysis a target section of single chromo-some from genome-wide in wheat.A powdery mildew resistance gene,Pm43,was assigned on the long arm of wheat 2D chromosome by Shanxi Key Laboratory of Crop Genetics and Molecular Improvement.Bioinformatics methods were used to determine the position of Pm43 in the physical map,genetic map and genome map in wheat.The re-sults provided a reference to the fine mapping or the candidate genes determining of Pm43.By aligning the se-quences of flanking markers,the Pm43 was mapped on the 79 -99 cM of C-2DL3-0.49 section,which was between 2DL_9835990 and 2DL_9823315 in genomic region.Using the conserved motifs of cloned resistance genes in wheat as a probe,89 RGA (Resistance gene analogues)-scaffolds were retrieved from the target region,and 36 scaffolds were containing SSR loci.Then SSR markers were developed.Applying the resistant (R)parent CH5025 carried Pm43,the susceptible (S ) parent Taichang 29 and two R /S bulks of F2 population crossed by CH5025 and Taichang 29,the linkage of developed SSR markers and Pm43 was detected.Four polymorphic markers were screened and further defined the target region between PK_9908430 and NBS_9908778.Then by cluster analysis, one PK sequence and one NBS sequence which had the highest homology with cloned Pm were screened,and their homologous RGA expressed sequences were found from Aegilopstauschii and rice genome.