CRK41调控微管骨架动态参与响应盐胁迫的作用机制

In plants, RLKs (receptor-like protein kinases) play essential roles in signal transduction by recognizing extracellular stimuli and activating the downstream signalling pathways. However, there are a lager number of RLK family members whose functions are still unknown. CRK41, a cysteine-rich receptor-like protein kinase screened by gene microarray, is located in the plasma membrane and induced by salt stress in our previous study. Based this interesting phenomenonon, the current project intends to study the signal transduction function of CRK41 in response to salt stress and explore its molecular mechanism. We want to reveal whether CRK41 regulates the dynamics of microtubules in response to salt stress. Furthermore, the signal pathway was explored to unravel whether CRK41 affects the MAPK signal pathway to regulate the stability of microtubule associated proteins, thus inducing the dynamics of microtubules. The project will contribute in filling the lack of functional research of CRK41 in Arabidopsis, and discover a novel gene and signal transduction pathway in response to salt stress. The study will shed new light on our understanding of the molecular regulatory mechanisms during salt stress in plant.

植物中类受体蛋白激酶识别胞外刺激并激活下游信号通路，在信号转导中发挥着重要作用。尽管数量众多，但只有少数成员功能已知。前期通过基因芯片筛选到富含半胱氨酸的类受体蛋白激酶CRK41定位于质膜且受盐胁迫的诱导表达。基于此，本课题拟对CRK41响应盐胁迫的信号转导功能进行研究，并探究其分子机制。通过研究内容揭示CRK41是否通过微管骨架动态响应盐胁迫；并对其信号通路进行探究，揭示CRK41是否影响MAPK信号途径进而调控微管结合蛋白稳定性，从而诱发微管动态变化。本项目的实施，补充了拟南芥CRK41功能研究的空缺，发现了拟南芥响应盐胁迫的新基因及其信号转导通路，为阐明植物响应盐胁迫的分子机理提供新的理论依据。

拟南芥中富含半胱氨酸的类受体激酶（CRKs）家族共46个成员，广泛参与调控植物生长发育、生物和非生物引起的逆境胁迫应答反应。然而，CRK41的功能和调控机制尚不清楚。本项目研究表明CRK41定位于细胞质膜，包括1个跨膜结构域，1个抗盐/抗真菌结构域、1个Ser/Thr激酶结构域以及DUF26结构域。本项目利用拟南芥野生型,CRK41缺失突变体，CRK41过表达株系，研究了CRK41调控拟南芥响应盐胁迫的作用机制。盐敏感表型观察和盐胁迫标志事件分析表明，crk41突变体表现耐盐胁迫表型，而CRK41的过表达导致拟南芥对盐更敏感。微管骨架动态分析表明，crk41突变体的微管解聚速度明显快于野生型，而CRK41过表达株系的微管解聚速度明显慢于野生型。进一步的分析表明，CRK41调控盐胁迫中MPK3和MPK6的表达，MPK3和MPK6也影响盐胁迫中微管的动态变化。杂交获得的crk41mpk3和crk41mpk6双突变体盐敏感表型与野生型类似，表明MPK3或MPK6失活均可使crk41突变体的耐盐胁迫能力丧失。且与crk41突变体相比，crk41mpk3和crk41mpk6双突变体的微管解聚速度减弱，表明CRK41抑制了MAPK介导的微管解聚。综上所述，CRK41通过与MPK3/6信号通路协同，在盐胁迫引发的微管解聚调控中发挥重要作用，而微管动态解聚是维持植物抗盐胁迫的关键因素。本研究为深入探讨植物响应盐胁迫的调控机制提供新思路。