水稻咪草烟抗性的遗传分析及其紧密连锁分子标记的筛选与应用

Genetic Analysis of Imazethapyr Resistance in Rice and the Closely Linked Marker Selection and Application

抗除草剂水稻的培育及推广能够提高除草效率,取得巨大经济效益。本研究中金粳818为抗咪草烟资源,以其与常规粳稻苏垦118杂交产生的F2群体对抗性基因进行遗传分析与分子定位表明,其抗性表型受1对显性核基因控制,位于水稻第2染色体SSR分子标记RM7413和RM7426之间。对该区间候选基因预测和测序发现,咪草烟靶基因-乙酰乳酸合酶基因(ALS)在重要功能位点发生1个碱基的突变(G变为A),导致一个氨基酸由丝氨酸(S)突变为天冬酰胺(N),初步确定ALS是抗性表型的重要候选基因。标记RM7413、RM7426与ALS的物理距离分别为165 kb、1612 kb。以金粳818与南粳9108为亲本,检测标记RM7413在辅助育种实践中的应用潜力,对杂交种及其自交后代进行连续表型及标记选择,F_7群体能够稳定遗传抗咪草烟性状,表明RM7413在粳稻抗咪草烟辅助育种中具有巨大应用潜力。本研究结果为粳稻抗除草剂分子标记辅助改良奠定了基础。

Cultivation and extension of herbicide-resistant rice can increase the efficiency of weed control and obtain great economic benefits. Here, Jinjing 818 was identified as an imazethapyr-resistant line, F2 population from the cross between Jinjing 818 and the conventional japonica rice Suken 118 was used for genetic analysis and gene mapping of the imazethapyr resistance in rice. The imazethapyr resistance in Jinjing 818 was controlled by a single dominant nuclear gene located between SSR markers RM7413 and RM7426 on the chromosome 2. Through gene-predicting and sequencing in this region, we found that the target gene of imazethapyr, acetolactate synthase gene （ALS）, had a nucleotide mutation （G mutated into A） in its coding region, leading to the mutation of serine into asparagine. It could be preliminarily deduced that ALS is the candidate gene for imazethapyr resistance. The physical distances between RM7413, RM7426 and ALS were 165 kb, 1612 kb, respectively. Jinjing 818 and Nanjing 9108 were used as parents to detect the application potential of RM7413 in molecular marker assisted selection breeding （MAS）. On the basis of selecting phenotype and RM7413 in the hybrid and its selfing generation, F7 population showed stable imazethapyr resistance, indicating that the great application potential of RM7413 in MAS and breeding for imazethapyr resistant rice. Our results will lay a foundation for breeding herbicide-resistant japonica rice by MAS.