水稻早衰突变体lst的生理分析与基因定位

Physisological Analysis and Gene Mapping of the Premature Senescence lst Mutant in Rice

本研究报道了一个来自EMS诱变优良恢复系浙恢7954的新水稻早衰突变体lst(Leaf senescence at tillering stage),其最主要的表型特点是叶片上出现锈色衰老斑,通过荧光共聚焦倒置显微镜观察和透射电子显微镜镜观察表明lst的叶绿素荧光减弱,叶绿体结构异常。生理生化分析发现lst突变体剑叶在早衰性状出现时,与野生型相比,其叶绿素和类胡萝卜素含量显著降低;O2-、H2O2、MDA含量升高,保护酶系统SOD和CAT活性降低。遗传分析表明,该突变体受1对隐性核基因控制,利用200株日本晴/lst的F2隐性定位群体,最终将LST基因定位在第3染色体SSR标记RM3646和InDel标记IAC120537-1,2之间,共171kb,含两个BAC,30个基因,这为基因的克隆和功能研究奠定了基础。

A new mutant of early secescence,lst（Leaf senescence at tillering stage）,was obtained from the rice restorer line zhehui7954,which was induced by EMS. the most important phenotype feature of the mutant is appeared rusty aging spots on leaves. Observation by fluorescence confocal inverted microscope and transmission electron microscope showed chlorophyll fluorescence decreased and abnormal chloroplast structure in lst mutant.The physiogical analysis showed that when the flag leaves of the lst appeared senescence traits, by contrast with the wild type, chlorophyll and carotenoid contents decreased significantly, while O2-、H2O2 and MDA contents increases significantly, and the activites of the protective enzyme system SOD and CAT deccreased. genetic analysis suggested that the mutantional trait was controlled by a nuclear recessive gene. Nipponbare was crossed with the lst and 200 mutational F2 single plants were used for genemapping.Finally,LST gene locus was mapped between SSR marker RM3646 and InDel marker IAC120537-1,2 on the chromosome 3 with physical distance of 171bp which contains two BAC and 30 gene. This result provides a foundation of LST gene cloning by map-based strategy as well as its functional analysis.