水稻化感抗（耐）杂草酚酸类物质代谢的相关基因调控

Allelopathy defined as process involving secondary metabolites produced by plant, algae, bacteria, and fungi that influence the growth and development of agricultural and biological systems. Allelochemicals from rice are secreted in the rhizosphere and suppress the growth of weeds.Phenolic compounds were earlier found as one of bioactive chemiclas from rice，however，there are few reports regarding to the genes coding the allelochemicals.The process of allelopathy is regulated by many genes such as signaling, allelochemicals synthesized and meterbolited by plant. Identification of genes in regulation of rice allelopathy is necessary and theorical meaning to understand the mechanism of allelopathy in rice..With strong allelopahic potential to some species of weeds, PI312777 was known as a standard material for evaluating rice lines. PI312777 also is a good material to carry out the further researches on relative genes identification and expression. In this research, PI312777 is used as one of the main material, and affected by artificial stress from weed, barnyardgrass, and then technique of gene chip and bio-informatics were used to analyze and select the relative genes in regulaion of rice allelopathy. And then expression vectors will be constructed and transferred into rice by the method of agrobacterium-mediated transformation for the functional verification. This research work may lay a foundation to identify or use the genes and well understand the mechanism in rice allelopathy.

水稻化感抗（耐）杂草指水稻通过根系分泌途径向环境中释放化学物质，从而抑制或影响周围杂草生长的作用，这是一个涉及信号接收与传导，抗性物质合成的多基因调控与代谢的过程。酚酸类化合物是水稻化感研究中发现较早的一类具有生物活性的化合物，但对这类化合物代谢调控的相关基因了解甚少。以化感水稻材料研究相关基因的表达和调控，对化感抗性机制的研究以及抗性性状利用具有理论和实践上的重要意义。.栽培稻PI312777具有良好的化感抗杂草性状，已成为水稻化感种质评价的标准参照，也是开展相关基因表达分析、基因克隆的良好材料。本研究将以化感水稻PI312777为材料，采用人工胁迫环境处理、基因芯片技术、生物信息学的分析比较，筛选与酚酸类物质合成相关抗性基因；构建表达载体、转化和功能验证，为进一步化感抗性基因利用、揭示水稻种质化感抗（耐）杂草机制奠定基础。

水稻化感抗（耐）杂草指水稻通过根系分泌途径向环境中释放化学物质，从而抑制或影响周围杂草生长的作用，是一个涉及信号接收与传导，抗性物质合成的多基因调控与代谢的过程。酚酸类化合物是水稻化感研究中发现较早的一类具有生物活性的化合物。以化感水稻为材料研究该类化合物合成代谢相关的基因表达和调控，对化感抗性机制的研究以及抗性性状利用具有重要的理论和实践意义。本研究以国际通用的化感水稻PI312777、非化感水稻Lemongt为材料，采用人工胁迫环境处理、基因芯片技术、生物信息学的分析比较，筛选与酚酸类物质合成相关抗性基因；结果表明，化感与非化感水稻材料在受到杂草胁迫后，8000多个基因响应了胁迫反应，其中近5000个基因上调表达，3000多个基因下调表达；通过生物信息学分析及信号通路分析发现抗逆相关基因40多个，与次生合成代谢相关基因30个，其中萜类（Terpernoid）合成代谢相关基因3个、固醇类（Steroids）合成代谢相关基因10个，而 Terpernoid合成的2个相关基因同时也是Steroids合成的相关基因；苯丙烷类合成代谢（Phenylpropanoid biosynthesis）相关基因10个；苯丙烷类合成代谢途径中酚酸类化合物合成酶编码基因C4H定位于细胞质及核中，受UV-B诱导大量表达，高表达C4H基因的水稻植株C4H酶活力大幅度提高接近化感水稻品种，酚酸类化合物的含量提高，其叶片水提液能明显抑制稗草根的生长，具有较好的化感潜力。本研究结果揭示了化感与非化感水稻的代谢通路完全不同，化感水稻以苯丙烷途径为主，非化感水稻以光合碳固定为主，酚酸类物质是水稻抗耐杂草的重要化合物之一，该代谢途径中肉桂酸-4-羟化酶编码基因C4H在化感材料中氨基酸的变异可能是抗耐杂草的原因之一。研究结果不仅为揭示水稻化感抗耐杂草调控的分子机制提供新的证据，也为化感抗性改良提供了基因资源。