番茄组蛋白去乙酰化家族基因的分离鉴定及其在抗青枯病中的功能研究

Tomato (Solanum lycopersicum) is the second most consumed vegetable in the world and the model of dicot as well. The productivity and quality of tomato fruits are often threatened by a broad range of plant diseases caused by fungi, bacteria, nematodes and arthropods. Ralstonia solanacearum is one of the most common soil-borne vascular diseases of the tomato crop. It is a herculean and longterm task for plant breeding workers to cultivate the germplasms of resistance to Ralstonia solanacearum. Study of tomato bacterial wilt resistance is one of the key and the difficult subjects of plant pathology. To cope with a lifetime of exposure to a variety of pathogens, plants have developed exquisite and refined defense mechanisms that vary depending on the type of attacking pathogen. Defense-associated transcriptional reprogramming is a central part of plant defense mechanisms. Chromatin modification has recently been shown to be another layer of regulation for plant defense mechanisms. Histone acetylation and deacetylation play an important role in the modification of chromatin structure and regulation of gene expression in eukaryotes. Histone deacetylases are involved in the activation of jasmonic acid and ethylene sensitive defence mechanisms. In plants, HDACs modulate the expression of developmental, stress-sensitive genes and defences against pathogens. Bioinformatics analysis indicated that there are 14 HDACs protein family members in tomato, SlHDT3 expressed most in root and up-regulated by R. solanacearum. And further more we will conduct research on the functional analysis of SlHDT3 in bacterial wilt resistance with the combination of molecular biology, cell biology, and biochemical technology, focusing on its roles in regulation of defemces in tomato.

番茄是世界重要的经济作物和公认的模式植物之一。由茄科雷尔氏菌侵染番茄引起的青枯病是严重影响华南地区番茄生产的重要细菌性病害；国内外学者一直致力于番茄抗青枯病高品质育种工作，至今却未能解决番茄抗青枯病的劣质连锁遗传问题。乙酰化是最早被发现的与转录有关的组蛋白修饰方式，组蛋白末端的乙酰化状态在组蛋白乙酰基转移酶（HATs）和组蛋白去乙酰基酶（HDACs）的作用下保持着动态平衡，并与染色质的转录活性状态密切相关，HDACs主要参与植物的形态发育和应对冷、干旱、抗病等胁迫过程。本研究组发现HDACs家族成员基因SlHDT3主要在根中表达，且在番茄抗青枯病品种接种后发现SlHDT3表达上调；因此本项目从SlHDT3与番茄抗青枯病的关系入手，研究该基因参与番茄抗青枯病的分子机制，将为利用分子生物学技术和基因工程手段改良番茄青枯病抗性奠定坚实的基础。

番茄是世界上重要的经济作物和公认的模式植物之一，由茄科雷尔氏菌侵染番茄引起的青枯病是严重影响华南地区番茄生产的重要细菌性病害。本项目通过系统研究番茄组蛋白去乙酰化酶家族基因分离鉴定、组织和胁迫表达分析、抗感病品种乙酰化修饰、抗青枯病反应通路及乙酰化修饰机制、载体及转基因研究、VIGS沉默基因的抗病表型分析等内容；研究发现青枯菌能够增加番茄抗病基因的组蛋白H3和H4的乙酰化水平，TSA处理能够增强番茄的抗青枯病能力，且发现SlHDT3转基因植株抗病性增强且与抗病基因SlWRKY80相互作用；本研究首次揭示了番茄抗青枯病的组蛋白修饰意义、阐明了抗感病品种的抗病表观遗传学机制、初步解析了组蛋白去乙酰化酶基因的抗病功能；本项目的工作虽然初步证明植物体内组蛋白乙酰化水平增加提高了番茄抗青枯病的能力，其具体的抗病及调控机制还不清楚，但该研究为后续开展该家族基因具体的抗病机制及分子功能和互作蛋白等方面提供了有益的线索。