药用野生稻转育后代一个抗白叶枯病新基因的定位

从药用野生稻渗入后代选育的水稻株系B5表现为高抗褐飞虱、白背飞虱和白叶枯病。对B5与籼稻品种明恢63杂交组合的187个重组自交系(RILs)进行了抗白叶枯病接种鉴定，采用分离集团分析法(Bulked Segregant Analysis，BSA)，在第1染色体上筛选到与水稻抗白叶枯病基因相连锁RFLP分子标记。利用RILs抗病性表现型鉴定资料和构建的分子标记连锁图谱，将抗白叶枯病基因定位在第1染色体短臂的C904和R596之间，这两个分子标记间遗传距离为1．3cM。该基因对RILs群体抗病性变异的贡献率为52．96％，是一效应值较大的主效基因。这一抗白叶枯病基因不同于已报道的抗白叶枯病基因的位点，因此将其命名为Xa29(t)。

Mapping of a New Resistance Gene to Bacterial Blight in Rice Line Introgressed from Oryza officinalis

Rice line 'B5',which was derived from the wild rice Oryza officinalis Wall ex Watt through introgression,has been proved to be high resistant to brown planthopper,whitebacked planthopper and bacterial blight (Xanthomonas oryzae pv.oryzae).In this study,the resistance to bacterial blight of 187 recombinant inbred lines (RILs) from a cross between 'B5' and 'Minghui63' were evaluated and RFLP markers linked to the resistance gene were identified by bulked segregant analysis.Analysis of the molecular marker linkage map and the data of the lesion length of RILs located the resistant gene within a 1.3 cM region flanked by RFLP markers C904 and R596 on chromosome 1.This locus contributed to 52.96% of the phenotypic variance of resistance in the population,and is considered to be a new locus as compared with other resistant genes to bacterial blight that have been reported.We tentatively designate this gene as Xa29(t).This newly tagged gene introgressed from wild rice is valuable to molecular marker-assisted selection for multiple resistant materials in rice breeding programme.Furthermore,it provides information for cloning the resistant gene Xa29(t) in rice.