转录因子WRKY70和ERF2-like在渐狭叶烟草抵御链格孢菌中的功能及作用机制研究
文献类型：学位论文
| ; | |
| 作者 | 宋娜 |
| 答辩日期 | 2021-05 |
| 导师 | 吴劲松 |
| 英文摘要 | Tobacco brown spot caused by Alternaria alternata is one of the most common fungal diseases in tobacco species. During the long-term co-evolution between plants and pathogens, host plants have formed a set of complex defense mechanisms to cope with the invasion of pathogens, including the formation of reactive oxygen species, physical enhancement of cell walls, and the production of plant hormones, proteins and metabolites. Phytoalexins are low molecular secondary metabolites produced de novo when attacked by pathogens. Our previous results showed that tobacco plants could accumulate two types of phytoalexin after infection with A. alternata, namely scopoletin and its glycoside form, scopolin, and sesquiterpene capsidiol. However, little is known about the regulation mechanism of scopoletin and capsidiol biosynthesis during infection. Nicotiana attenuata, a diploid wild tobacco, was used as a model plant to study the molecular regulation of scopoletin and capsidiol biosynthesis by A. alternata, through combination of biochemical, molecular biological and chemical methods such as transcriptome analysis, virus-induced gene silencing (VIGS), RNAi, gene overexpression, protein and DNA interaction. The main results were as follows: 1, NaWRKY70, a transcription factor, is the key regulator of scopoletin synergistically induced by jasmonate (JA) and ethylene (ET) signaling. JA and ET signaling pathways in N. attenuata were activated by A. alternata, and synergistically regulated scopoletin production and the expression of key enzyme gene feruloyl-CoA 6?-hydroxylase 1 (NaF6’H1). Accordingly, scopoletin biosynthesis could be dramatically induced by exogenous treatments of methyl jasmonate and ethephon simultaneously, but not by methyl jasmonate or ethephon along. Through transcriptome analysis and gene silencing methods, a WRKY family transcription factor, NaWRKY70, was identified as the key regulator of scopoletin during its synergistic induction by JA and ET. 2, NaWRKY70 directly regulates the expression of NaF6’H1, the key enzyme gene involved in scopoletin biosynthesis, and A. alternata-induced NaWRKY70 is under the control of NaMYC2 and NaEIN3-like, the two master regulators of JA and ET signaling. Electrophoretic mobility shift assay (EMSA) and transcriptional activation experiments showed that NaWRKY70 bound to the W-box elements in the promoter regions of NaF6’H1 and activated its transcription to regulate the scopoletin accumulation. NaMYC2 and NaEIN3-like, the key factors of JA and ET signaling, were demonstrated to be required for the A. alternata-induced NaWRKY70 by VIGS. 3, NaWRKY70 is required for A. alternata-induced jasmonic acid-isoleucine (JA-Ile) and abscisic acid (ABA) biosynthesis, two plant hormones essential for N. attenuata resistance to A. alternata. NaWRKY70 regulated JA-Ile biosynthesis through directly binding to the promoters of the Allene oxide synthase (NaAOS), which coding a key enzyme of JA-Ile biosynthesis. |
| 源URL | [http://ir.kib.ac.cn/handle/151853/74642]  |
| 专题 | 昆明植物研究所_昆明植物所硕博研究生毕业学位论文 |
| 推荐引用方式 GB/T 7714 | 宋娜. 转录因子WRKY70和ERF2-like在渐狭叶烟草抵御链格孢菌中的功能及作用机制研究, Study on the regulation of defense responses to Alternaria alternata by two transcription factors WRKY70 and ERF2-like in Nicotiana attenuata[D]. 2021. |
入库方式： OAI收割
来源：昆明植物研究所
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