广西野生稻Y11抗白背飞虱QTL定位

Mapping of QTLs for resistance to white-backed planthopper in Guangxi wild rice Y11

白背飞虱是危害水稻生产最严重的害虫之一。培育抗性品种是防治白背飞虱最经济有效的措施。本研究发现广西野生稻‘Y11’高抗白背飞虱,‘Y11’植株上白背飞虱的数量及存活率均显著低于感虫品种‘广恢998’,表现出较强的排趋性和抗生性。为解析‘Y11’抗白背飞虱的遗传基础,以‘Y11’为供体亲本,籼稻品种‘广恢998’为轮回亲本,构建了BC_(3)F_(9)回交重组自交系群体,并完成了该群体白背飞虱苗期抗性鉴定及全基因组连锁图谱的构建,进行了抗白背飞虱QTL (quantitative trait locus)检测。结果发现,在水稻2号、6号和11号染色体上检测到3个抗性位点,分别命名为qWBPH2^(Y11), qWBPH6^(Y11)和qWBPH1^(Y11),其LOD值分别为4.8、2.5和3.7,分别解释表型变异的9.3%、2.3%和5.6%,且3个QTL的抗性等位基因均来自于广西野生稻‘Y11’。进一步从BC_(3)F_(9)回交群体中挑选携带qWBPH2位点的家系继续与‘广恢998’回交2次,经标记辅助选择,获得了qWBPH2的近等基因系,近等基因系的白背飞虱抗性显著高于背景亲本‘广恢998’。上述抗白背飞虱QTL的定位及近等基因系的构建,为抗性基因克隆及通过分子标记辅助选择培育抗性品种奠定了基础。

White-backed planthopper(WBPH)is one of the most serious pests in rice production.Breeding resistant varieties is the most economical and effective strategy to control the white-backed planthopper.In this study,we found that Guangxi wild rice variety‘Y11’had high resistance to white-backed planthopper.The number and survival rate of WBPH were significantly less than the susceptible variety‘Guanghui 998’.These results showed that‘Y11’displayed higher antixenosis and antibiosis against WBPH.Subsequently,‘Y11’was as the donor parent and an indica cultivar‘Guanghui 998’was as the recurrent parent by con-tinuous backcrossing and selfing to obtain the BC_(3)F_(9) population.Furthermore,to identify the quantitative trait locus(QTL)for white-backed planthopper resistance,we completed the evaluation of this population for WBPH resistance at seedling stage and constructed the genome-wide linkage map.Three QTLs were detected on the three different rice chromosomes,and designed as qWBPH2^(Y11),qWBPH6^(Y11),and qWBPH11^(Y11),respectively.The LOD values were 4.8,2.5,and 3.7,which accounted for 9.3%,2.3%,and 5.6%of the phenotypic variation,respectively.All of the resistance alleles were from resistant parent‘Y11’.Plant harboring qWBPH2^(Y11) was selected from BC_(3)F_(9) population to continuously backcross with‘Guanghui 998’.The near isogenic line of qWBPH2^(Y11) was developed by molecular marker assisted selection,which displayed higher resistance to WBPH than the back-ground parent‘Guanghui 998’.The mapping of WBPH resistance QTLs and the development of the near isogenic line in this study will be helpful for cloning resistance genes and breeding resistant in rice cultivars.