紫茎泽兰查尔酮合酶基因在羟基泽兰酮代谢途径中的作用

Eupatorium adenophorum is a kind of noxious invasive alien weed origin from Mexico and Costarica. It has some characteristics such as strong vitality and toxicity; it also can spread rapidly, absorb nutrients from soil strongly, and produce allelochemicals.?At present, Eupatorium adenophorum has widely distributed about 30 countries and regions at tropical and subtropical zones. In these regions, it has seriously threatened the ecological system of forest and farmland..Allelotaphy is one of important factors in aspect of efficient invasion, and it is also the focus in studying the invasion mechanism of E. adenophorum. Various researches on E. adenophorum have been conducted. However, most studies have focused on separating and purifying of allelochemicals, and its physiological function to receptor plants. Research had showed that HHO is one of main allelochemicals in E. adenophorum. Moreover, chalcone synthase of E. adenophorum is closely related to metabolism of HHO..In this project, we will separate and analyze the major gene of chalcone synthase gene family in first place, which induced by HHO in E. adenophorum. Furthermore, over expression vector containing the full length of major gene and RNA interference vector will be constructed in order to transfer them into E. adenophorum using agrobacterium-mediated transformation method. In addition, interaction between the major gene and other key genes of second metabolic pathway will be illustrated. The difference in dose of HHO between transgenic plant and wild type as well as its effect on growth and development of receptor plant will also be explored..Our final objective is to reveal the function of chalcone synthase gene in metabolic pathway of HHO in E. adenophorum. It will provide the theory basis in studying the metabolic network of HHO in E. adenophorum.

紫茎泽兰是一种入侵性很强的恶性杂草。它具有生命力强，传播速度快，植株本身能分泌有害的化感物质等特点，已经对入侵地的农、林、畜牧业生产造成了严重的危害。化感作用是紫茎泽兰有效入侵的一个重要因素，也是入侵机制研究的热点。目前，紫茎泽兰化感作用的研究主要集中在化学活性物质的分离及其对受体植物的生理水平的影响，已有研究表明羟基泽兰酮（HHO）是紫茎泽兰的主效化感物质之一，而紫茎泽兰查尔酮合酶与HHO的代谢密切相关。本项目从鉴定紫茎泽兰查尔酮合酶基因家族中响应HHO诱导的主效基因入手，针对该基因构建植物过量表达载体及RNA干涉载体并转化紫茎泽兰，分析该主效基因与其他次生代谢相关基因的调控关系，比较分析转基因植株同野生植株在羟基泽兰酮分泌剂量方面存在的差异，以及对受体植物生长发育影响的差异，明确紫茎泽兰查尔酮合酶在化感物质-羟基泽兰酮代谢途径中的作用，为研究紫茎泽兰化感物质的代谢通路提供理论参考。

紫茎泽兰是一种入侵性很强的恶性杂草。它具有生命力强，传播速度快，植株本身能分泌有害的化感物质等特点。化感作用是紫茎泽兰有效入侵的一个重要因素，也是入侵机制研究的热点。目前，紫茎泽兰化感作用的研究主要集中在化学活性物质的分离及其对受体植物的生理水平的影响，而对于化感物质作用的分子机制研究还很少。.本项目从鉴定紫茎泽兰查尔酮合酶基因家族中响应HHO 诱导的主效基因入手，针对该基因构建植物过量表达载体及RNA干涉载体并转化植物，分析紫茎泽兰查尔酮合酶基因对于次生代谢产物的影响以及同次生代谢途径中其他关键基因的调节关系，并研究了该基因在植物应对盐胁迫所发挥的生物学功能，研究结果表明：查尔酮合酶基因的表达同植物次生代谢过程中其他关键酶编码基因的表达存在协同调控关系，这种协同调控可能与植物中的“代谢频道”存在有关；该基因同样对于下游次生代谢产物具有重要的调控作用，但基因的超量表达与下游产物的产量并没有呈现相应比例关系，这可能与植物化感代谢途径中存在化感分流作用有关，该作用会分流浓度高的代谢产物进入到其他代谢途径，以调节细胞避免受到过高浓度次生代谢物的毒害。盐胁迫作为非生物胁迫的一种，能够通过调节植物体内活性氧（ROS）的产生和积累来影响植物体的氧化还原状态，而SOD、CAT等抗氧化酶可以阻止活性氧的产生与积累，从而提高植物对于胁迫的耐受性。本研究发现在盐胁迫处理下，紫茎泽兰查尔酮合酶基因的表达可以改变植物体内活性氧清除过程中一些关键酶的活性以及一些重要小分子的含量，结合次生代谢产物含量的测定结果，我们得到的结论是：紫茎泽兰查尔酮合酶基因可以通过改变植物体内类黄酮的积累并调节植物体内活性氧平衡来实现植物对于盐胁迫的耐受。上述结果将为紫茎泽兰化感物质的作用机制研究提供理论参考。.