水稻细菌性条斑病抗性基因bls2 SSR分子标记开发

Development of SSR molecular markers for bacterial leaf streak resistance gene bls2 in rice(Oryza sativa L.)

【目的】开发水稻细菌性条斑病(简称细条病)抗性基因bls2 SSR分子标记,为利用分子标记辅助选择培育水稻细条病抗性品种提供技术支撑。【方法】基于本课题组前期对细条病抗性基因bls2初定位结果,设计SL03与SL04分子标记区间的SSR引物,从中筛选出在亲本间具有多态性的引物,用于检测由普通野生稻DY19与籼稻9311为亲本构建的BC_(3)F_(2)群体中各单株的基因型,并结合细条病病斑长度测定结果,利用MapQTL 5.0精细定位bls2基因,鉴定出与之紧密连锁的SSR分子标记,并比较单标记或双标记的选择效果。【结果】通过田间细条病抗性鉴定发现,BC_(3)F_(2)群体抗、感分离符合理论比1∶3的孟德尔单基因遗传分离规律。利用筛选鉴定出的11个多态性分子标记对BC_(3)F_(2)群体共244个单株进行单株基因型检测,并结合单株抗性表型值,将细条病抗性基因bls2精细定位于2号染色体上RM13592和RM13599分子标记之间,物理距离240 kb;RM13592和RM13599分子标记在BC_(3)F_(2)群体上的分离比均符合1∶2∶1的单基因遗传分离规律。利用单标记和双标记均可有效选择BC_(3)F_(3)群体中的感病单株和抗病单株。RM13592和RM13599分子标记辅助选择符合率分别达92.62%和93.44%,使用双标记的选择符合率为93.44%。【结论】RM13592和RM13599与细条病抗性基因bls2紧密连锁,具有易于PCR扩增,易于识别,准确性高的特点,可作为水稻抗细条病育种上分子标记辅助选择的有效标记。

【Objective】SSR markers closely linked to the resistance gene bls2 against bacterial leaf streak(BLS)were developed in order to provide technical support for the cultivation of BLS-resistant rice varieties by molecular marker-assisted selection(MAS).【Method】Based on the preliminary mapping of the resistance gene bls2,the SSR markers were designed in the interval of markers SL03 and SL04 and those primers with polymorphism between parents were screened to detect the individual genotype in BC_(3)F_(2) population which was bred by common wild rice DY19 and indica rice 9311 as parents.Combined with the measurement results of the length of lesions caused by BLS,bls2 gene was fine mapped by software MapQTL 5.0,therefore the SSR markers closely linked to bls2 were determined and the selection effects of unilateral and bilateral markers were compared.【Result】It was found that the segregation of resistant and susceptible plants in BC_(3)F_(3) population accorded with Mendelian monogene segregation of 1∶3 by resistance identification to BLS in field.Eleven pairs of polymorphic markers between parents were screened to detect the genotypes of 244 individual plants in BC_(3)F_(2) population,then the location of the resistance gene bls2 was mapped to the physical distance of 240 kb between markers RM13592-RM13599 on chromosome 2 combined with individual phenotype identification.Both markers RM13592 and RM13599 segregated at ratio of 1∶2∶1,which was completely agreement with monogene searegation law.In BC_(3)F_(3) population,the use of unilateral marker RM13592 or RM13599 and the simultaneous use of bilateral markers were effective for the selection of susceptible and resistant plants.The MAS selection accuracies of unilateral markers RM13592 and RM13599 were 92.62%and 93.44%respectively,while the selection accuracy of bilateral markers was 93.44%.【Conclusion】RM13592 and RM13599 are closely linked to the resistance gene bls2 and have the characteristics of easy PCR amplification,easy identification and high accuracy,so they can be used as effective markers of MAS in breeding rice variety against BLS.