拟南芥LFR在非生物逆境响应中的作用及机制研究

Sessile plants are continuously subjected to various abiotic stresses, which not only affect plant growth and reproduction, but also the biomass and crop yields we human being mainly depend on. Epigenetic regulatory mechanisms play a crucial role in terms of stress adaptation，and among them the ATP-dependent chromatin remodeling is now causing widespread concern. Arabidopsis LFR gene was reported firstly in our laboratory and was characterized as a new subunit of plant specific ATP-dependent chromatin remodeling complexes. On one hand, we will use the LFR-related genetic material obtained in our previous work, to analyse the phenotypic under salt, drought, cold, heat, hormone and other stress conditions; on the other hand we will carry on a variety of physiological, biochemistry, molecular and genetic techniques to elucidate the downstream target genes of LFR; Furthermore, we will further study the chromatin state of target gene by using of biochemical and molecular biologial methods to explore the possible molecular mechanisms of LFR regulation of target genes. The relevant results will help us to elucidate the molecular mechanism of chromatin regulation in higher plant stress adaptation, and lay the theoretical foundation for the genetic improvement of plants.

固着生长的植物不断受到来自于环境的非生物逆境胁迫，这对人类赖以生存的农作物的产量造成巨大的影响。表观遗传调控机制在生物对逆境胁迫的响应和适应方面起到至关重要的作用，其中ATPase依赖的染色质重塑在植物逆境适应中的作用正引起广泛关注。本课题组首报的拟南芥功能基因LFR是ATP依赖的染色质重塑复合体新组分。本课题组将利用我们前期获得的LFR相关的遗传材料，一方面分析其在盐、干旱、冷、热等胁迫条件下以及激素处理条件下的表型；另一方面我们将借助多种生理、生化、分子和遗传等技术手段，寻找LFR调控的可能的下游靶基因；再者，我们将进一步利用生化和分子手段研究靶基因的染色质状态，探究LFR调控靶基因的可能的分子机制。相关结果将有助于深入阐明高等植物逆境适应的染色质调控的分子机理，为提高植物抗逆性的遗传改良奠定理论基础。

干旱和土壤盐渍化是影响农作物生长、发育及产量的非生物胁迫之一, 对参与干旱和盐胁迫响应的功能基因的研究将有助于揭示植物胁迫响应的分子机制。本研究借助生理、生化、分子、细胞和表观遗传多层面的技术手段阐明了LFR参与逆境胁迫如，盐胁迫、干旱胁迫的分子机制。lfr功能缺失突变体对盐胁迫敏感， 盐胁迫SOS信号通路中的SOS1在lfr中的受诱导程度显著低于野生型, 这与lfr突变体盐敏感表型相吻合, 可能是导致lfr突变体对盐胁迫敏感的诱因之一；另外，参与盐胁迫等多种逆境的染色质重塑ATPase CHR23在lfr突变体中的表达上调明显，体内实验证明它是LFR的直接靶基因，LFR可以影响该基因染色质的组蛋白修饰水平。同时，lfr功能缺失突变体还表现出对干旱耐受和对ABA敏感的表型，ABA处理后并和ABI5存在遗传学的相互作用。上述结果预示着LFR可能通过调控染色质水平的变化调控逆境胁迫相关基因的转录表达，参与植物对盐胁迫的响应。