C4H的转录调控因子对水稻化感抗耐杂草的调控机制

Allelopathy is a mechanism of adaptation to environment /defense against to adversity for the organism. The pests management by allelopathy is to take full advantage of the organism own defense or resistance. Phenolic compounds were the earliest found as one of bioactive chemiclas from rice. Analysis/understanding the molecular mechanism between allelopathy to weed and the compounds synthesis is one of the important research fields for rice genetic and stress resistance. Supported by the National Science Foundation of China, our research found that CYP73A38, a key gene for the synthesis of phenolics, wa closely related to allelopathic potential to barnyardgrass, and also found that there were differentially expressed transcriptional regulators between allelopathic and non-allelopathic rice cultivars, which suggested that there are different mechanisms of transcriptional regulation. In this study, we will continue to reveal the molecular regulator of phenolic compounds in rice. The cDNA library will be constructed by allelopathic rice PI312777 after weed stress, and the transcriptional regulatory factors binding to CYP73A38 promoter sequence will be screened by yeast one hybridization, and the expression pattern of the selected factors will be analysis to understand/select the exogenous induction factor for improvement rice allelpathic potential to weed. And then expression vectors and site-directed mutagenesis genetic material will be constructed and transferred into no-allelopathic rice by the method of agrobacterium-mediated transformation for the functional verification of these factors to further reveal the mechanism between phenolics metabolism and rice allelopathy to weed. We believe that the research results will reveal the molecular mechanism of phenolic compounds synthetic metabolism, and be benefit to improve/apply weed suppression ability in rice.

化感作用是生物对环境的一种适应机制或对逆境的防御机制。酚酸类是最早发现的具有生物活性的水稻化感物质，解析化感抗杂草作用与该类化合物合成代谢的分子调控机理是水稻遗传与抗逆生物特性研究领域的重要课题之一。在国家自然科学基金项目资助下，我们研究发现酚酸类物质合成的关键基因CYP73A38与化感抗性表达密切相关，同时发现在化感和非化感水稻中存在差异表达的转录调控因子，推测其抗性的差异是不同的转录调控机制。本项研究在前期工作的基础上，拟构建化感水稻PI312777受杂草胁迫的cDNA文库，运用酵母单杂交手段筛选与CYP73A38基因启动子序列结合的转录调控因子，分析这些转录因子基因的表达模式，通过构建转录因子高表达载体及定点突变遗传材料来进行功能来验证，进一步揭示酚酸类物质代谢与化感抗杂草的分子调控机制。研究结果对水稻抗耐杂草性状的改良、揭示酚酸类物质合成代谢分子机理以及化感抗耐性应用具有理论和实际

化感作用是生物对环境的一种适应机制或对逆境的防御机制。酚酸类是最早发现的具有生物活性的水稻化感物质，解析化感抗杂草作用与该类化合物合成代谢的分子调控机理是水稻遗传与抗逆生物特性研究领域的重要课题之一。本项研究运用酵母单杂交技术筛选与酚酸代谢相关基因CYP73A38启动子序列结合的转录调控因子，通过分析这些转录因子基因的表达模式，筛选出候选调控因子，并通过构建转录因子高表达载体及定点突变遗传材料来进行功能来验证，以揭示酚酸类物质代谢与化感抗杂草的分子调控机制。研究结果对水稻抗耐杂草性状的改良、揭示酚酸类物质合成代谢分子机理以及化感抗耐性应用具有理论和实际应用的重要意义。.通过构建化感水稻PI312777受杂草胁迫的cDNA酵母文库，以CYP73A38编码基因Os05g0320700启动子序列为诱饵菌株对文库进行筛选，酵母单杂交筛选、互作验证后获得PHL7、ERF67、ERF68、NAC18等14个候选蛋白，其中ERF类转录因子在化感与非化感水稻中表达量的变化较大，将ERF67、ERF68两个转录因子蛋白作为候选调控因子。构建高表达、定点突变载体构建及遗传转化，获得转基因植株。ERF67和ERF68均定位于细胞核中。在ERF67高表达植株中，Os05g0320700的表达相比对照下降，而基因敲除植株中，Os05g0320700的表达相比对照上升，ERF67高表达材料中酚酸类物质含量低于对照，而突变体材料高于对照，突变体植株对稗草根生长的抑制率更高。结果表明OsERF67、OsERF68通过直接抑制CYP73A38的编码基因Os05g0320700的表达来调控植物的酚酸类物质合成，从而负调控水稻的杂草抗（耐）性。