小粒野生稻抗白叶枯病新基因的鉴定与初步定位

【目的】将小粒野生稻(Acc.No.101133)的抗白叶枯病基因导入栽培稻IR24,并对其进行鉴定和分子标记定位,以便应用于育种实践。【方法】以小粒野生稻和栽培稻IR24的BC2F2群体及其F3、F4家系为材料,利用分离集团分析法(BSA),借助SSR标记对Xa35(t)进行分子标记定位。【结果】通过对抗病基因进行抗谱鉴定和遗传分析,结果表明,该基因对白叶枯病菌株PXO86和PXO99表现感病,而对PXO61、PXO112和PXO339表现抗病,初步将其定位于水稻的第11染色体长臂上,同标记RM144共分离,并位于标记RM7654和RM6293之间,与两标记的遗传距离分别为1.1cM和0.7cM。【结论】小粒野生稻(Acc.No.101133)含有新的抗白叶枯病基因,暂定为Xa35(t)。

Identification and Mapping of a Novel Bacterial Blight Resistance Gene Xa35(t) Originatd from Oryza minuta

【Objective】 A new rice bacterial blight resistance gene from the wild rice species Oryza minuta (Acc. No. 101133) was transferred into Oryza sativa L. (IR24). Identification and molecular mapping of the resistance gene was carried out to put it into practical use in the future. 【Method】 A BC2F2 population and its F3, F4 families were used for molecular mapping of Xa35(t), and Bulked Segregant Analysis (BSA) was adopted to survey SSR markers. 【Result】 Through genetic analysis and identification of resistance spectrum, Xa35(t) showed a high level of resistance to PXO61, PXO112 and PXO339, but susceptible to PXO86 and PXO99 after inoculation with five strains of Xanthomonas oryzae pv. oryzae (Xoo), suggesting it is a new dominant bacterial blight resistance gene in the long arm of chromosome 11. With SSR marker analysis, the Xa35(t) locus was mapped to a region of about 1.80 cM. This locus, co-segregated with marker RM144, was 0.7 cM from marker RM6293 on one side and 1.1 cM from marker RM7654 on the other side in rice chromosome 11. 【Conclusion】 Genetic analysis and identification of resistance spectrum revealed that Oryza minuta (Acc. No. 101133) harbors a new rice bacterial blight resistance gene, designated as Xa35(t).