水稻早衰突变体esl6的鉴定与基因定位

发布时间：2018-06-03 08:19

本文选题：水稻(Oryza + sativa　；参考：《作物学报》2016年07期

【摘要】：自然衰老提高了植物对环境的适应性,是其生长发育的重要生命历程,但在农业生产中,叶片一旦早衰,将极大影响作物的产量和品质。为探索水稻叶片衰老的分子机制,我们对EMS诱变获得的一个早衰突变体esl6进行了研究。田间种植情况下,四叶期之前,esl6与野生型无明显差异,之后心叶发育成完整叶后叶尖黄化,叶基部保持正常绿色,一直持续到开花期;在灌浆期,esl6的所有叶片均不同程度地黄化早衰,且叶片上部的衰老程度明显严重于叶片基部。衰老部位细胞结构异常,主要表现为细胞膜破裂、液泡变大和细胞器不完整等,叶绿体中基质类囊体破裂,含有较多的淀粉粒。与野生型相比,esl6叶尖衰老部位的SOD、CAT和POD活性以及超氧阴离子O_2?~、H_2O_2和羟自由基·OH含量均极显著升高。早衰不仅导致esl6叶片光合色素含量和净光合速率极显著降低,还引起esl6的植株变矮和叶片变短,倒一和倒二节间极显著变短是导致esl6植株矮化的主要原因。遗传分析表明该性状受一对隐性核基因调控,利用西大1A/esl6的F_2分离群体,最终将调控基因定位在第9染色体203 kb的物理范围内,为下一步基因的克隆和功能研究奠定了基础,有利于水稻叶片衰老分子机制的阐释。
[Abstract]:Natural senescence improves the adaptability of plants to the environment and is an important life course of their growth and development. However, in agricultural production, the yield and quality of crops will be greatly affected by the premature senescence of leaves. In order to explore the molecular mechanism of leaf senescence in rice, we studied the esl6 of a premature senescence mutant induced by EMS. Under field planting, there was no significant difference between the four leaf stage and the wild type, but after the heart leaf developed into a complete leaf, the tip of the leaf was yellowish, and the base of the leaf remained normal green until the flowering period. At the filling stage, all leaves of ESL 6 were yellowed and prematurely aged to varying degrees, and the senescence degree of upper part of leaf was more serious than that of leaf base. The cell structure of senescence was abnormal, such as cell membrane rupture, vacuole becoming larger and organelle incomplete, and matrix thylakoid broken down in chloroplast, which contained more starch granulocytes. Compared with the wild type, the activities of SOD cat and POD and the content of superoxide anion O _ 2 and H _ 2O _ 2 and hydroxyl radical OH in senescent site of the leaf tip of esl6 were significantly higher than those of the wild type. Premature senescence not only decreased the photosynthetic pigment content and the net photosynthetic rate of esl6 leaves, but also caused the plants of esl6 to become shorter and shorter, and the first and second internodes of esl6 were significantly shorter, which was the main cause of the dwarfing of esl6 plants. Genetic analysis showed that the trait was regulated by a pair of recessive nuclear genes. Using FST2 isolated population of Xida 1A/esl6, the regulatory gene was mapped within the physical range of chromosome 9 203kb, which laid a foundation for further gene cloning and functional study. It is helpful to explain the molecular mechanism of senescence in rice leaves.
【作者单位】：西南大学水稻研究所/转基因植物与安全控制重庆市重点实验室;
【基金】：中央高校基本科研业务费(XDJK2013A023) 国家自然科学基金项目(31171178)资助 supported by the Fundamental Research Funds for the Central Universities(XDJK2013A023) the National Natural Science Foundation of China(31171178)
【分类号】：S511

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