水稻单叶独立转绿型黄化突变体grc2的鉴定与基因精细定位

摘要

Green revertible leaf-color mutants are basical materials for studying the mechanism of chloroplast differentiation and development. We have obtained agreen-revertible chlorina mutant namedgrc2 with every leaf greening independently, from an indica maintainer line T98B treated by60Co-γ radiation. Each leaf ofgrc2 is initially chlorotic, and then turns green after growing about 10 days. The mutantgrc2 showed a new pattern of virescence which refreshed green regardless of its plant growth stage. Compared with the wild type T98B, the total chlorophyll and chlorophyll b content reduced significantly in the yellowish leaves ofgrc2 and chloroplast remained in the etioplast stage, suggesting thatgrc2 would probably be an essential gene functioning in the development of young leaves. Genetic analysis revealed that,grc2 was controlled by a single recessive nuclear gene. The gene ofgrc2 was fine mapped between STS markers S254 and S258 with a physical interval of 31 kb on the short arm of chromosome 6, by using 960 F2 plants with mutant phenotype from a cross betweengrc2 and Nipponbare. This region contained five annotated genes that had not published. These results provides important information for studying in gene cloning and gene function ofgrc2.%转绿型叶色突变体是研究植物叶绿体分化与发育的基础材料。grc2是利用60Co-γ射线诱变籼型三系保持系T98B后获得的单叶独立转绿型黄化突变体。grc2植株上任一叶片刚抽出时为黄色，在生长10 d左右后变绿，具有单叶不依赖于植株特定发育阶段而独立转绿的特性。与野生型T98B相比， grc2黄化叶片的总叶绿素和叶绿素b含量显著降低，叶绿体滞留在黄化质体阶段，表明grc2可能在叶片早期发育中起关键作用。遗传分析表明， grc2受1对隐性核基因独立控制；利用源于grc2/Nipponbare的F2群体的960个突变单株，将grc2基因定位在STS标记S254与S258之间约31 kb的范围内，该区域含有5个未报道过的注释基因。这些结果为grc2的克隆及功能研究提供了重要信息。