【摘要】 基因聚合是培育广谱、持久抗性水稻品种的有效策略。然而,水稻白叶枯病隐性抗性基因xa5和一些抗病基因组合后却产生了拮抗的聚合效应。为避免无效或拮抗的组合,有必要对携带单基因和基因组合的水稻品种进行抗性评价。调查了2个感病水稻系(籼稻IR24和粳稻TP309),4个单基因抗病系IRBB3、IRBB5、IRBB21和CBB23(分别含Xa3、xa5、Xa21和Xa23)和3个多基因抗病系IRBB54、IRBB50和IRBB59(分别含xa5+Xa21、xa5+Xa4、xa5+Xa21+xa13)对8个白叶枯菌小种的抗性。前期对xa5、Xa21单基因和基因聚合后的效应进行了报道,发现江汉大学保存的P8小种克服了Xa21介导的抗性。发现P8在TP309和IRBB3上都诱导8个小种中最长的病斑,进一步证明了P8致病力的变异;IRBB54、IRBB50和IRBB59对包括P8在内的8个小种表现出抗性,表明了基因聚合策略应对致病菌毒性变异的有效性;而Xa23单基因对所有小种的抗性都达到了三基因聚合系IRBB59的高抗性水平,但在和xa5聚合后抗性被弱化,呈现负向的拮抗效应。研究结果提示在进行水稻基因聚合育种时,应充分考虑小种的致病性变异和基因聚合的多效性。更多还原

【Abstract】 Gene pyramiding is an effective strategy for breeding broad-spectrum and persistent resistance rice varieties. However, the combination of rice bacterial blight(BB) resistance gene xa5 with some BB resistance genes produced an antagonistic effect. In order to avoid ineffective or antagonistic combinations, it is necessary to evaluate the resistance of rice varieties carrying single gene and gene combinations. We investigated two susceptible rice lines(Indica rice IR24 and Japonica rice TP309), four single-gene resistant lines IRBB3, IRBB5, IRBB21 and CBB23(containing Xa3,xa5,Xa21 and Xa23, respectively), and three gene pyramiding lines IRBB54, IRBB50 and IRBB59(containing xa5+Xa21,xa5+Xa4 and xa5+Xa21+xa13, respectively) to eight BB strains. The previous reports on the resistance of xa5 and Xa21 single genes showed that the P8 strain overcame the resistance mediated by Xa21.In this study, we found P8 induced the longest lesion of eight strains on both TP309 and IRBB3, which further confirmed the variation of pathogenicity of P8; IRBB54, IRBB50 and IRBB59 showed resistance to all eight strains, indicating the effectiveness of gene pyramiding strategy in dealing with virulence variation of pathogen. The resistance of Xa23 gene to all strains reached the level of IRBB59,but it was weakened after pyramided with xa5,showing a negative antagonistic effect. The results suggested that the pathogenicity variation of stains and the multidirectional effect of gene pyramiding should be fully considered in rice breeding.更多还原