二甲基砷诱发水稻直穗病形成的生理机制与水稻直穗病抗性的分子基础研究

水稻直穗病在我国很多稻区均有发生，且呈逐年扩大趋势，给农业生产造成重大损失，然而该病致病机理尚不清楚，导致目前仍无有效防控措施。根据申请人前期工作及相关研究进展，我们认为直穗病是二甲基砷(DMA)在水稻穗部过量积累引起的，但DMA诱发水稻直穗病的毒性机制并不清楚，不同水稻品种对直穗病抗性差异的遗传基础也有待解析。本项目基于申请人前期研究结果，利用不同直穗病抗性水稻材料开展实验，明确DMA诱发水稻直穗病的关键生育期和剂量效应，阐明DMA毒性对水稻幼穗发育各时期形态结构、细胞活性以及基因表达谱的影响；并以幼穗DMA含量、活性氧簇（ROS）及抗氧化酶活性等毒理指标为表征，对幼穗蛋白组、代谢组差异进行系统生物学分析，探明DMA诱发水稻直穗病的毒性机制。同时本项目也将对一个控制水稻直穗病抗性的主效数量性状基因座（QTL）中关键基因进行鉴定与克隆。本项目将为水稻直穗病防控与品种抗性改良提供理论依据。

Rice straight-head disease is prevalent in many rice producing areas in China. The area affected by this disease has been increasing which results in great yield losses to agricultural production. There are no effective preventive solutions for straight-head disease in rice production due to the reasons and the underlying mechanisms remain unclear. Based on the results from our previous studies and research of others, we believe that dimethylarsenate (DMA) accumulation in rice panicles is the primary reason for straight-head disease. However, the toxic mechanism of DMA induced straight-head disease is indistinct, meanwhile, genetic basis of resistance/susceptibility in rice in response to the disease is also unclear. In this project, we will conduct pot experiments to identify the sensitive growth stage of rice and dose effect of DMA on straight-head disease. The effects of DMA toxicity on morphological structure, cell activity and transcriptome of young panicles will be investigated. Together with relevant toxicological indicators, systematic analysis of the differences in proteome and metabolome of young panicles between DMA treatment and the control will be performed to elucidate the mechanism on how DMA causes straight-head disease in rice. Simultaneously, we aim to clone the gene in a previously identified main-effect quantitative trait locus (QTL) responsible for rice straight-head disease resistance. This project aims to provide theory evidence to the development of prevention solutions for rice straight-head disease and basic knowledge for breeding rice varieties with high straight-head disease resistance.