茶丽纹象甲危害诱导的茶树防御机制相关酶基因发掘

Enzyme Genes Related to Defense Mechanism in Tea Plant Induced byTea Weevil (Myllocerinus aurolinealus Voss) Feeding

为揭示茶树被茶丽纹象甲取食诱导的分子防御机制,以取食诱导叶片为处理组,以未取食叶片为对照组,利用转录组测序法获得茶树新梢叶片被茶丽纹象甲危害前后的差异基因表达谱,并从中筛选茶丽纹象甲危害诱导的茶树防御机制相关的酶基因。结果表明,COG功能比对共获得39 037个注释,包括25个功能类别,其中防御机制功能类别包含的单基因数为316个;KEGG功能比对共获得27 075个注释,包括363个生物代谢通路;从COG比对结果的防御机制功能类别中筛选出差异表达酶单基因簇8个,均上调表达,涉及的代谢通路包括MAPK信号路径、类黄酮生物合成、丙酮酸代谢、萜类生物合成、苯丙氨酸代谢,基于KEGG代谢通路分析,初步归纳了8个防御机制相关酶之间的关系。RT-qPCR分析结果表明,8个酶单基因在茶丽纹象甲取食茶树新梢叶片后72 h内均上调表达,其中双特异性磷酸酶3、双特异性MAP激酶磷酸酶、花色素还原酶、二氢黄酮醇4-还原酶、NADPH依赖的丙酮醛还原酶基因表达差异主要由机械损伤作用导致。本研究结果为进一步深入开展茶丽纹象甲危害诱导的茶树分子防御机制研究及其抗性茶树种质鉴定提供了参考。

In order to reveal the defense mechanism of tea plant leaves induced by tea weevil（Myllocerinus aurolinealus Voss） feeding, selected defense related enzyme genes from the differential gene expression profile between the tea weevil damage-induced tea shoot and the undamaged control obtained by RNA-seq technology. The results showed that, 39,037 unigenes were categorized into 25 functional groups based on COG database. Among them, 316 unigenes were categorized in the defensive function. 27,075 unigenes were assigned to 363 signal pathways by function prediction through the KEGG database. From the defense function category obtained by COG analysis, identified 8 significantly differentially expressed unigenes, which were all up-regulated, involved in MAPK signal path, flavonoids biosynthesis, pyruvate metabolism, biosynthesis of terpenoids and phenylalanine metabolism. Based on the KEGG metabolic pathway analysis, we preliminarily clarified the relationships among the 8 enzymes related to defense. Furthermore, RT-qPCR showed that 8 unigenes were all up-regulated expressed within 72 h after tea weevil feeding. The expression differences of those unigenes（dual specificity phosphatase 3, dual specificity MAP kinase phosphatase, anthocyanidin reductase, dihydroflavonol reductase, NADPH-dependent methylglyoxal reductase） were mainly caused by mechanical damage. This research is capable of providing a reference for studying the molecular defense mechanism of tea weevil feeding and giving a guidance for selecting tea weevil resistant tea plant germplasm in future.