水稻早衰突变体esl3的鉴定与基因定位

叶片早衰直接降低作物的光合作用、产量和品质。因此，鉴定早衰突变体和研究其基因功能对于作物的遗传改良具有重要的作用。esl3来源于水稻籼型恢复系缙恢10号的EMS诱变库，苗期叶片中上部即呈现褐化枯萎，该特征一直持续到植株成熟。与野生型相比，突变体衰老部位叶绿素和光合速率极显著下降，绿色部位光合色素和光合速率则略有升高。农艺性状分析发现，结实率无显著变化，有效穗、穗长、穗粒数、千粒重、株高和干物质重则显著或极限著下降。遗传分析表明，esl3叶片早衰枯死性状受1对隐性核基因控制。利用391株日本晴/esl3的F₂突变型单株，最终把ESL3基因定位在第5染色体SSR标记RM19085和Indel标记Ind05-2之间，物理距离91 kb，包含14个注释基因，为下一步调控基因的克隆和功能研究奠定了基础。

Identification and Gene Mapping of Rice Early Senescent Leaf (esl3) Mutant

Leaf early senescence can directly decrease crop photosynthesis, yield and quality. Therefore, the identifications of mutants with early senescence and its gene function play key roles in crop genetic improvement. A mutant with early senescent leaf blades, named as esl3, was identified from a EMS-induced progeny in restorer line of Jinhui 10. The middle-upper leaf in mutation displayed a brown and withered phenotype from seedling stage to maturity. Correspondingly, the chlorophyll content and net photosynthetic rate declined in the abnormal leaves while enhanced in the normal green part of leaves compared with the wild type. Agronomic traits, such as panicle number, panicle length, grains per panicle, 1000-grain weight, plant height and weight of dry matter, were reduced significantly or very significantly except for seed setting rate as compared with those of wild type. Genetic analysis showed the senescence was controlled by a recessive nuclear gene. Using 391 mutation individuals in a F₂ generation of Nippomese/esl3, ESL3 was mapped between SSR marker RM19085 and Indel marker Ind05-2 on the chromosome 5 with physical distance 91 kb including 14 annotated genes. All of these results provide a foundation for the further gene cloning and functional analysis of ESL3 gene.