拟南芥丝氨酸羧肽酶SCPL41基因在干旱胁迫中的作用及机制

Signal transduction during drought stress has been well studied, but many important signal components and genes involved in drought stress response have not to be determined yet. We previously obtained a transferred DNA (T-DNA) insertion Arabidopsis mutant (renamed as bis4) which was identified as a loss of-function mutant with defective in SCPL41 gene transcription. The bis4 mutant wasinsensitive to abscisic acid (ABA) and very sensitive to drought stress. The function of SCPL41gene has not been reported in plant physiological processes and environmental stress response. In this project, the wild-type, the insertional mutant and 35S::SCPL41 line are exposed to exogenous ABA or drought stress, and then we analyze (1) drought tolerance; (2) the express pattern, the location of SCPL41-GFP in cell and the histochemical localization of SCPL41; (3) the express pattern and the location of SCPL41-GFP in cell and the histochemical localization of SCPL41; (4) the protein changes upon alteration of SCPL41 protein expression levels by conducting iTAIQ, and to screen the changed protein which related with.ABA or drought stress; Thus, we want to reveal the molecular mechanism of Arabidopsis SCPL41 gene in response to drought stress and fill gaps in understanding the ABA-dependent signal pathway during drought stress and provide a new candidate gene for improving crop stress tolerance.

植物应答干旱胁迫的信号途径以及与之相关的脱落酸途径已有深入研究，但仍有许多关键信号分子和基因有待发现。我们前期筛选到脱落酸不敏感的拟南芥T-DNA插入突变株，序列分析表明其是丝氨酸羧肽酶类蛋白基因SCPL41的转录表达缺失产生的，并发现缺失和过表达该基因的植株对干旱分别表现出敏感和抗性，但该基因的生物学功能和环境响应调控功能尚且未知。本项目拟通过比较野生型、SCPL41缺失和过表达植株，经外源脱落酸和干旱处理：（1）系统的生理生化差异；（2）SCPL41的表达样式和细胞、组织定位；（3）iTAIQ技术检测蛋白表达，筛选受SCPL41蛋白调控且与脱落酸、干旱胁迫相关的差异蛋白；（4）蛋白水解酶活性检测，验证上述差异蛋白作为SCPL41蛋白底物的特异性。探明SCPL41在干旱胁迫中的作用机制，为阐释干旱胁迫中信号通路尤其是依赖于脱落酸的信号途径提供新知识，为作物抗旱性状的改良提供新的候选基因。

干旱严重影响农业生产，其机制已有深入研究，特别是ABA 信号在干旱响应中的作用，但是仍然有许多重要环节未知，参与干旱胁迫响应的基因有待发现。本研究用拟南芥野生型、SCPL41基因缺失型和过表达型株系对比检测了的的ABA响应表型，干旱耐受性，发现SCPL41基因过表达是通过ABA途径来提高植株干旱耐受性。同时检测了拟南芥野生型、SCPL41基因缺失型和过表达型株系的蛋白表达谱，转录组检测了差异基因表达谱，进一步证实SCPL41基因可通过ABA信号途径来提高植株干旱耐受性。初步应用酵母双杂筛选了与SCPL基因编码蛋白互作的蛋白，目前尚无筛选到互作蛋白。将SCPL41基因过表达到油菜中同样可显著提高油菜的干旱耐受性。通过检测膜脂组成发现，SCPL41基因可能是通过调控干旱下膜脂重组来实现提高干旱耐受性。