一个新的水稻黄绿叶突变体的遗传分析及突变基因的精细定位

Genetic Analysis of a New Yellow-green Leaf Mutant and Fine-mapping of Mutant Gene in Rice

在水稻品种Dongjin的T-DNA插入突变体库中筛选到一份黄绿叶突变体T113,该突变体在生长的整个时期叶片都呈现黄绿色,且越到后期表型越明显。T113与野生型亲本Dongjin相比,叶片光合色素含量明显降低,株高变矮,结实率降低,每穗着粒数、穗长和千粒重均明显减少,抽穗期延迟,且黄绿叶性状不受温度影响,叶绿体中的类囊体排列较为疏松,出现更多的嗜锇体,叶绿素合成和质体发育相关基因表达量发生改变。遗传分析表明,T113的突变性状由1对隐性核基因控制。利用T113/N22的F2群体,将突变基因定位在第2染色体长臂Indel标记CX2和JX18之间,物理距离约为79 kb,此区间内包含12个预测基因。

The yellow-green leaf mutantT113, which was isolated from a T-DNA mutant pool with Dongjin variety as the back-ground material, showed a yellow-green leaf phenotype in whole developing stage. Compared with wild type, the contents of chlorophyll and carotenoid decreased, the yellow-green leaf became more and more obvious along with developing inT113. At maturity, the number of productive panicles per plant, panicle length, seed setting rate, 1000-grain weight and plant height reduced. The date of heading ofT113 also delayed. The phenotype of mutant was not affected by temperature. Ultrastructural analysis showed that the chloroplast of mutant was brighter than that of wild type, the mutant developed loosed thylakoid lamellar struc-tures. The expression of genes associated with chlorophyll biosynthetic and chloroplast development ofT113changed a lot. Ge-netic analysis showed that the yellow-green leaf trait of theT113 mutant was controlled by one pair of recessive nuclear genes. Genetic mapping of the mutant gene was conducted using a F2 mapping population ofT113/N22. Finally, the mutant gene was mapped between Indel markers CX2 and JX18 on the long arm of chromosome 2 with physical distance of 79 kb, in which 12 predicted genes had been annotated.