水稻OsNOX2抗旱的分子机制及其调控信号研究

NADPH oxidases (NOXs) are key enzymes in the production and metabolism of reactive oxygen species (ROS),playing vital roles both in plant growth development and stress responses. Previously, we found that at least 11 NOX-encoding genes exist in rice genome and their expressions exhibited obvious spatio-temporal characteristics under various stress conditions, implying their diverse functions in rice stress response and development. Among these NOX genes, OsNOX2 expression was strongly stimulated by drought stress, and an OsNOX2-dependent stress signalling pathway was found to be involved in the stress responses of rice. However, the molecular mechanism for the involvement of OsNOX2 in drought tolerance of rice and its regulatory signalling pathways are still under investigation. In the present project, a series of rice gene knockout mutants as well as a number of molecular and physiological approaches including gene cloning, genetic transformation, gene expression of organization and subcellular localization, protein interaction and proteomic analysis, and physiological measurements will be used for futher investigation to clarify the molecular mechanism of OsNOX2 in rice drought tolerance. Functions of several genes such as OsRTPK1, OsRTPK2, and OsmtATPS1, which might play crucial roles in the OsNOX2-dependent stress signalling pathway, will be specifically studied in the project, with emphasis on their interactions with OsNOX2 in rice stress responses and development.

质膜NADPH氧化酶（NOX）是植物活性氧释放与代谢的关键酶，对植物生长发育调控和环境胁迫响应均至关重要。我们的前期研究表明，水稻NOX酶家族至少有11个成员且其表达具有明显的时空调控特点与逆境响应偏好性；其中OsNOX2基因表达受干旱强烈诱导且一条以OsNOX2为中心的酪氨酸受体蛋白激酶依赖的信号通路被发现可能参与了水稻对干旱逆境的响应，然而OsNOX2抗旱的分子机制尚未阐明，其信号调控途径尚需要更直接的实验证据支持。本项目拟在这些前期研究的基础上，利用相关水稻突变体，通过基因克隆、遗传转化、组织与亚细胞定位表达、蛋白互作分析、蛋白质组学研究、以及理化测定等手段，深入研究OsNOX2抗旱的分子机制及其调控信号通路中几个关键调控节点基因如OsRTPK1、OsRTPK2、OsmtATPS1等的功能，明确这些节点基因与OsNOX2表达之间的关系，阐明OsNOX2抗旱的分子机制及其关键调控信号。

NADPH氧化酶（NOX）是ROS释放的关键酶，在植物正常发育调控和逆境胁迫响应种均具有重要作用。我们在前期研究中发现水稻中具有9个典型的NOX蛋白，其中OsNOX2受干旱胁迫强烈诱导表达，但其参与植物逆境胁迫响应的机制并不明确。本项目主要进行水稻OsNOX2基因功能及其抗旱的分子调控机制。在项目研究中，我们严格按照项目申请提交的内容和进度安排开展工作，完成了项目总体目标，达到了预期研究效果，取得了一系列重要研究结果，具体如下：①克隆了水稻OsNOX2基因，创制了该基因表达缺失突变体、过表达和沉默表达转基因植株，发现OsNOX2过表达显著提高了水稻植株的抗旱性；②采用RT-PCR、基因芯片、表型与生理生化分析等手段，阐明了OsNOX2的抗旱性及其表达特点，提出了一条水稻OsNOX2介导的抗旱信号通路；③采用生物信息学及表达分析手段，系统研究并明确了植物NOX家族基因的系统进化关系和逆境表达特征，发现NOX家族成员功能多样并广泛参与植物逆境胁迫响应；④克隆了6个与OsNOX2表达调控密切相关的基因，并对其功能分别进行深入研究，初步阐明了OsNOX2基因抗旱的分子调控机制。这些研究结果对进一步认识NOX家族基因的功能及其抗逆机制具有重要参考价值。其次，本项目研究中我们在Plant Physiology、Genome Biology and Evolution、Plant Cell andPhysiology、Physiologia Plantarum等国内外权威学术期刊上发表论文11篇（均标注基金资助），其中SCI论文10篇，产生了重要的学术影响。另外，本项目研究中培养研究生13名，其中博士研究生7名，毕业硕士研究生6名，取得了良好的社会效益。