水稻苗期根部性状的遗传分析和最长根长QTL qLRL4的精细定位

Genetic analysis of seedling root traits and fine mapping of the QTL qLRL4 for the longest root length in rice

为了解析水培苗期根系相关性状的遗传调控,以籼稻9311和粳稻日本晴(Nipponbare, NPB)为亲本的148个株系构成的重组自交系群体为材料,对水稻幼苗根系相关性状开展QTL分析。在2次重复中共检测到26个控制最长根长、总根系长、根表面积、根体积和根直径的QTL,分布在水稻第1、2、4、7、9、10、11号共7条染色体上,发现了水稻第2、4、7和10号染色体上的4个QTL簇,包括第4号染色体上控制最长根长的QTL qLRL4。为了精细定位该QTL,我们构建了以9311为背景、插入缺失标记IND4-1和IND4-4间来自NPB的近等系NIL-qLRL4。利用NIL-qLRL4和9311构建的F2群体,最终将qLRL4精细定位在标记IND4-1和IND4-3之间约68.23 kb的区间内并预测了候选基因。此根长QTL的精细定位将有助于水稻根长遗传机理的研究,为探究水稻根系形态建成的分子机制奠定了基础。

In order to analyze the genetic basis of root traits at seedling stage,we performed QTL analysis of root morphology with 148 recombinant inbred lines derived from indica variety 9311 and japonica variety Nipponbare(NPB).In two repetitions,a total of 26 QTLs were detected for the longest root length,total root length,root surface area,root volume,and root diameter,distributed on chromosomes 1,2,4,7,9,10,and 11 in rice.Four QTL clusters on chromosomes 2,4,7,and 10 were found,including a major QTL qLRL4 controlling the longest root length.To fine mapping of the major QTL,we constructed a near isogenic line NIL-qLRL4 with a segment from NPB between markers IND4-1 and IND4-4 with 9311 background.With a F2 population derived from the NIL-qLRL4 and 9311,we fine mapped the qLRL4 within~68.23 kb region between markers IND4-1 and IND4-3,where eight candidate genes located.Fine mapping of this QTL for root length will help explore genetic mechanism of root elongation and morphogenesis in rice.