盐胁迫下拟南芥微丝解聚因子AtADF1的作用及其机制

The microfilament (MF) plays a pivotal role in many cellular processes that regulate cell growth and morphology. Recent studies have indicated that MFs participate in the response to salt stress in Arabidopsis, but the mechanism remains unclear. We examined the expression of actin depolymerizing factor AtADF family genes in Arabidopsis. The result showed that the expression of AtADF1 was up-regulated. Moreover, Atadf1 mutants were hypersensitivity in response to salt stress and suppressed salt inducible high expression of SOS2 and SOS3. These results indicate that AtADF1 is involved in plant salt tolerance. In this proposal, the expression patterns of AtADF1 will be analyzed in salt stress treatments by Real-time PCR, Western blot, GUS activity analysis. The phenotypes and the organization and dynamics of MFs will be observed in AtADF1 overexpressing, Atadf1 mutants and rescue lines under salt stress. The function of interaction between AtADF1 and SOS pathway members will be studied by genetical and pharmacological methods under salt stress. These results will explain the mechanism of AtADF1 positively regulate Arabidopsis salt tolerance, providing theoretical basis for the mechanism of MF in plant salt tolerance.

微丝在植物生长发育等很多方面具有重要功能。有研究表明微丝是植物适应盐胁迫的重要因子，但作用机制仍不清楚。申请人前期研究发现盐胁迫能够诱导拟南芥微丝解聚因子AtADF1表达上调， AtADF1突变体植株对盐胁迫超敏感，且植株中盐诱导的SOS2和SOS3表达上调受到抑制，表明AtADF1参与拟南芥耐盐过程并起到重要作用。本项目拟通过Real-time PCR、Western blot、GUS活性检测等方法研究盐胁迫下AtADF1的表达模式；利用活体观察微丝组织动态等技术研究AtADF1过表达、突变体及回复突变体植株在盐胁迫下的生长表型变化及微丝骨架的组织动态变化；并利用遗传学、药理学等方法研究AtADF1与SOS途径成员之间的作用关系，从而阐明微丝解聚因子AtADF1正调控拟南芥耐盐性的作用机制，为盐胁迫下微丝作用机理提供新的科学理论依据。

有研究表明微丝是植物适应盐胁迫的重要因子，微丝结合蛋白是调节微丝动态变化的主要因子，但是目前却未见关于微丝结合蛋白参与植物盐胁迫响应的报道。AtADF1是一种微丝解聚因子，本项目以拟南芥野生型、AtADF1过表达和突变体植株为实验材料，通过明确盐胁迫下微丝解聚因子AtADF1的表达模式，观察盐胁迫下野生型、AtADF1过表达和突变体的表型及微丝组织动态变化，并检测野生型、AtADF1过表达和突变体植株中SOS家族基因的表达变化情况，从而揭示盐胁迫下微丝解聚因子AtADF1的功能。