十字花科蔬菜抗虫硫苷代谢及调控的分子机理研究

Glucosinolates are an important group of secondary metabolites enriched in Cruciferous vegetables. Some of their hydrolysates are important anti-insect compound. The glucosinolate profiles are significantly different between Chinese cabbage and leaf mustard. Diamondback moth and Beet armyworm have special and omnivorous diets, respectively. So, we planed to find the key glucosinolate component for insect resistance in the interaction process between the two kinds of vegetables and two pests. And the growth, physiological and biochemical metabolism of the pests will also be investigated after feeding. Then, the key genes for glucosinolate metabolism will be screened by RNA-Seq to make a basic network for understanding the molecular mechanism of the regulation and metabolism of glucosinolates during the interactions mentioned above. On this basis, we will screen the key genes on the signal transduction and glucosinolate metabolism during the interactions. The expression pattern of the key genes could be characterized through qRT-PCR, promoter fusion expression, and so on. Their biological functions will be identified by over-expression and RNA interference methods. In a word, these studies will provide a theoretical support for understanding the anti-insect function of glucosinolates in the interaction process between cruciferous vegetables and insects, and the molecular mechanism of the increased insect resistance of plant after insects feeding. It could also lay a theoretical foundation for breeding of new cruciferous vegetables cultivars with enhanced insect-resistance , except for the production of safe vegetables.

十字花科蔬菜富含一类重要的次生代谢物质-硫代葡萄糖苷，其水解产物具有较强的抗虫能力。本项目以硫苷组成和含量差异较大的大白菜和叶用芥菜为材料，研究它们在与专食性、杂食性昆虫互作过程中起到害虫防御作用的关键硫苷组分与含量的变化的异同，并分析害虫取食后生长发育和生理生化代谢的异同；通过转录组测序(RNA-Seq)等方法，对该互作过程中的植物硫苷代谢及调控关键基因在全基因组水平上建立一个基本网络框架，进而深入解析相关抗虫硫苷代谢及调控的分子机理；在此基础上，筛选该互作过程中信号转导和硫苷代谢相关的关键基因，通过qRT-PCR、启动子融合表达等技术分析其时空表达模式，利用过表达和RNA干涉等方法鉴定它们的生物学功能。这些研究将为明确硫苷在十字花科蔬菜与害虫互作过程的作用及害虫取食提高植物抗性的分子机制提供理论支撑，为抗虫十字花科蔬菜新品种培育及蔬菜安全生产提供理论依据和技术支持。

十字花科蔬菜富含一类重要的次生代谢物质-硫代葡萄糖苷(硫苷)，其水解产物具有较强的抗虫能力。研究硫苷在蔬菜与昆虫互作过程中的重要防御作用及其分子机制，将有助于提高十字花科蔬菜的营养安全品质、对居民健康及经济社会的发展具有重要意义。.通过项目研究发现，二丙烯基硫苷是叶用芥菜抵御害虫取食的关键硫苷，而4-羟基吲哚-3-甲基硫苷、4-戊稀基硫苷、吲哚-3-甲基硫苷和1-甲氧基吲哚-3-甲基硫苷是白菜抵御害虫取食的几种关键硫苷。芥菜中53个硫苷合成与调控相关基因在害虫取食后的表达出现显著差异，白菜中9个硫苷合成与调控的关键基因（BCAT4、MAM1、SUR1、MYB28、AOP2、SOT16、CYP83A1、CYP83B1和APK2）的表达量都在害虫取食后显著提高。在芥菜的6个BjuMYC2s和白菜的12个BrSOTs基因中，BjuAMYC2和BrSOT16-1这两个基因在虫吃胁迫和MeJA处理后表达量升高的差异最显著，重点针对这两个基因成功构建了它们的启动子融合表达、过表达和RNAi干涉载体，利用农杆菌介导的方法分别对叶用芥菜和白菜进行了遗传转化，获得了各载体的相应转基因株系，对这些转基因材料生物学性状的全面解析能够为揭示它们在抗虫硫苷代谢及调控中的功能奠定理论基础。eATP处理能通过ET和JA途径影响硫苷的合成与调控，显著提高白菜叶片中脂肪族和根中吲哚族硫苷的含量。