脂氧合酶在稗草应答靶向除草剂抗性演化中的分子机理

前期研究发现脂氧合酶（LOXs）在稗草（Echinochloa crus-galli (L.) Beauv）应答靶向除草剂抗性演化进程中起着重要作用，但其功能知之甚少。本申请项目拟从植物对除草剂的胁迫诱导、信号传导及其处理胁迫环境能力来审视杂草抗药性机理。本项目拟以遗传背景一致的系列稗草（多抗、单抗与敏感）为材料，靶向药剂为二氯喹啉酸与五氟磺草胺，采用农药学、植物学等多学科研究手段，首先阐明靶向除草剂胁迫下，各处理植物形态学与光合生理特征参数；并分析其根、茎与叶片候选植物激素（茉莉酸、水杨酸等）含量动态变化；克隆并阐明供试稗草间LOXs的生物学功能差异性，分析LOXs基因与关键调控因子表达特征，最后探明靶向除草剂胁迫下，稗草种间脂氧合酶信号途径并佐证其功能，发掘农田杂草抵御靶向除草剂的作用模式。研究结果将阐明脂氧合酶介导杂草防御靶向除草剂胁迫的分子机理，为作物绿色增产增效提供新的理论依据。

Previous work demonstrated lipoxygenases (LOXs) played a crucial role in the evolution of herbicide resistance in Echinochloa crus-galli (L.) Beauv response to targeted herbicide. However, little is known about the function of LOX associated with herbicide resistance mechanisms in resistant weed species. This research intends to examine the mechanism of weed resistance from herbicide- induced, signal transduction and environmental stress processing. In this study, the E. crus-galli populations with single or multiple herbicide resistances to the commonly used herbicide quinclorac and penoxsulam have been collected. The resistant populations with the same genetic background will be characterized and used for this study together with the susceptible populations. The morphology and physiological characteristic parameters under targeted herbicide stress will be investigated among these populations by means of pesticide science, botany and other multidisciplinary research methods. The dynamic changes of candidate plant hormones (jasmonic acid, salicylic acid, etc.) in root, stem and leaf will be analyzed to reveal expression patterns of LOXs and key regulators in resistant E. crus-galli. Furthermore, the LOX gene will be cloned to evaluate the diverse biological functions of LOXs involved in herbicide resistance in E. crus-galli populations. Finally, the LOX signal pathway in E. crus-galli response to targeted herbicides will be captured and functional characterization of LOXs will be conducted to determine the protective patterns of weeds against herbicides. The results will help better understand the molecular mechanisms of weed resistance mediated by lipoxygenase in response to targeted herbicides. It will also provide the theoretical support for improving grain yield in rice.