水稻短根毛突变体Ossrh2的表型分析与基因定位

Phenotypic Analysis and Gene Mapping of a Short Root Hair Mutant Ossrh2 in Rice(Oryza sativa)

在粳稻品种中花11为遗传背景的T-DNA突变体库中筛选获得一个遗传稳定的水稻(Oryzasativa)短根毛突变体Ossrh2(Oryza sativa short root hair2)。突变体在苗期表现为根毛数量减少,为野生型的61.4%,根毛长度明显变短,只有野生型的22.8%,同时根毛增粗,根毛形态也发生了变异,局部扭曲膨胀和分叉,除此之外突变体的地上部和根部生长情况与野生型相比没有显著差异。遗传分析表明,该突变性状受1对隐性单基因控制。通过对突变体T2和F2代的分子检测发现,该突变体表型非T-DNA插入引起。利用Ossrh2纯合体和籼稻品种Kasalath杂交构建的F2群体对OsSRH2进行基因定位,发现其与第10号染色体短臂上的SSR(simple sequence repeat)标记RM6370和RM474连锁,遗传距离分别为1.1cM和3.0cM。通过在两标记间发展3个新的STS(sequence-taggedsite)标记,将OsSRH2基因定位于标记S1227和S1531之间,物理距离约为304kb,为进一步克隆OsSRH2打下了基础。

A rice（Oryza sativa） mutant with short root hairs（Ossrh2） was isolated from a T-DNA insertion mutant library of rice in the Zhonghua11 background.Except for root hairs,Ossrh2 did not differ from the wild type.The number and length of root hairs of Ossrh2 were only 61.4% and 22.8%,respectively,that of the wild type,and hairs were thicker.The root hairs of Ossrh2 were also morphologically abnormal and showed distortion,swelling and branching.Genetic analysis revealed that the mutant phenotype was controlled by a single recessive nuclear gene.PCR analysis of T2 and F2 mutants showed that the phenotype was not caused by T-DNA insertion.To map the OsSRH2 gene,we generated an F2 popula-tion by crossing the mutant Ossrh2 with the Kasalath wild type.OsSRH2 was first mapped between the microsatellite markers RM6370 and RM474 on the short arm of chromosome 10 with genetic distance of 1.1 and 3.0 cM,respectively.Then,3 new polymorphic sequence-tagged site markers were developed in the region.OsSRH2 was finally mapped between markers S1227 and S1531 with a physical distance of 304 kb,which would help in its cloning.