棉花CMS系花药氧应激在雄性败育中的作用及产生机制

项目名称： 棉花CMS系花药氧应激在雄性败育中的作用及产生机制

项目编号： No.30800694

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 朱云国

作者单位： 同济大学

项目金额： 19万元

中文摘要： 本项目通过TUNEL分析、活性氧积累的细胞学观察、线粒体内膜跨膜电位 (Δ936;m) 检测、细胞色素c的免疫细胞学观察、活性氧清除能力分析、线粒体呼吸链主要基因序列和表达分析等，对棉花CMS系花药氧应激在雄性败育中的作用及产生机制进行了研究。结果发现：（1）棉花CMS系雄性败育是因为其花粉母细胞发生了PCD；（2）棉花CMS系败育时雄性细胞的线粒体最先出现H2O2积累并向细胞质扩散，揭示线粒体是CMS系花药氧应激的源头；（3）棉花CMS系的coxⅢ基因发生了突变，导致花药线粒体细胞色素氧化酶活性降低和呼吸链出现缺陷，是线粒体活性氧大量产生的根本原因；（4）棉花CMS系花药及其线粒体中的活性氧清除能力低下，进一步加剧了活性氧产生与清除的失衡，最终导致花药活性氧大量积累，并形成严重的氧应激；（5）棉花CMS系花药雄性细胞及其线粒体中的氧应激会导致线粒体内膜跨膜电位(Δ936;m)的丧失和细胞色素c的释放，从而介导PCD的发生。上述结果证实了我们提出的"棉花CMS系花药氧应激介导PCD导致雄性败育"的假说，首次阐明了棉花CMS的形成机制，对植物雄性不育机理研究和杂种优势利用具有重要的理论和实践意义。

中文关键词： 棉花；细胞质雄性不育；细胞程序性死亡；线粒体；活性氧

英文摘要： The role and the generation mechanism of oxidative stress in the cytoplasmic male-sterile (CMS) cotton anthers were investigated by TUNEL assay, cytological observation on the accumulation of reactive oxygen species, mitochondrial membrane potential (Δ936;m) survey, cytochrome c release observation, reactive oxygen species scavenging capacity analysis and mitochondrial respiratory chain gene sequences and expression analysis. The results showed that: (1) pollen abortion of CMS cotton because of its pollen mother cells occurred programmed cell death (PCD); (2) H2O2 accumulation first appeared on mitochondria in abortive male cell of CMS cotton and cytoplasmic diffusion revealed the mitochondria were the source of oxidative stress; (3) coxШgene mutations leading to mitochondrial cytochrome oxidase activity decreased and respiratory chain defects were the root causes of a large number of reactive oxygen species production in the mitochondria of CMS cotton anthers; (4) CMS cotton anthers and its mitochondria's reactive oxygen species scavenging capacity were low, further exacerbating the imbalance between production and scavenging of reactive oxygen species, eventually leading to the accumulation of a large number of reactive oxygen species and the formation of severe oxidative stress; (5) oxidative stress in the mitochondria could cause the loss of the mitochondrial membrane potential (Δ936;m) and cytochrome c release, thus mediated the occurrence of PCD. These results demonstrate our hypothesis of "oxidative stress in CMS cotton anthers causes male cell occurrence PCD", clarify the formation mechanism of cotton CMS and are benefit for clarification the formation mechanism of CMS and utilization of hybrid vigor in plants.

英文关键词： cotton; cytoplasmic male sterility; programmed cell death; mitochondria; reactive oxygen species