依赖ABA的角质层调节途径中关键基因SPS的克隆与功能解析

The cuticle is the outer physical barrier of aerial plant surfaces, which protects plants from dehydration. During extreme drought episodes, stomata are mostly closed, the rate of cuticular transpiration is of particular importance for plant survival. Therefore, cuticle can be a potential ideal target for drought tolerance improvement in plants. However, the cuticle regulatory pathways are largely unknown, which limited the application of cuticle adjustments in the modification of plant drought tolerance..Recently, we revealed that cuticle is manipulated by the ABA classical signaling pathway. Further studies showed that the SnRK2 regulated a cuticle-specific signaling, which is independent of the stomata signaling and the ABA-responsive element binding proteins (AREB/ABF) derived signaling. To dissect this cuticle-specific signaling, we carried out a genetic screen for the suppressor of snrk2.236 and successfully got two candidates renamed with suppressor of permeable-cuticle of snrk2.236 (sps) 1 and sps2..In this study, we aim to isolate the genes of these two sps mutants; use approaches of gene expression, protein-protein interaction, stress response test and cuticle component analysis to study the mechanisms of regulation of SnRK2 on SPS; dissect the SPS-regulated signaling and monitor the impacts of SPS on cuticle formation and plant drought tolerance. We believe that this study will significantly extend our knowledge about cuticle and also provide candidate gene targets for cuticle modifications.

角质层是覆盖在植物表面的，负责保持植物水分的屏障。在干旱的时候，植物气孔关闭，水分主要通过角质层散失。调节角质层的保水能力对改良植物耐旱有重要作用。然而，角质层的调节途径一直没有解析，限制了角质层在抗旱改良中的应用。.我们前期的研究发现，角质层受到ABA经典途径的调节，并且在SnRK2下游存在一条特异调节角质层的、不依赖于气孔途径或ABA相应元件结合因子（AREB/ABF）调节途径的分支途径。为解析该分支途径，我们对SnRK2家族的SnRK2.2、2.3、2.6的三突变体snrk2.236的抑制基因进行了筛选，并得到2个候选抑制基因突变体 (sps)。.本研究旨在克隆sps的突变基因，并通过基因表达、蛋白互作、逆境生理分析、角质层成分分析，解析SPS对SnRK2下游的角质层分支途径的调节机制及其对植物耐旱的影响，为通过角质层调节植物耐旱的实际应用提供理论基础和靶点基因。

角质层是覆盖在植物表面的，负责保持植物水分的屏障。在干旱的时候，植物气孔关闭，水分主要通过角质层散失。调节角质层的保水能力对改良植物耐旱有重要作用。然而，角质层的调节途径一直没有解析，限制了角质层在抗旱改良中的应用。.通过本次研究，我们研究发现，角质层受到ABA经典途径的调节，并且在SnRK2下游的SPS基因来调节角质层；SPS可以被SnRK2磷酸化；其非磷酸化的形式对角质层的形成有负向作用。进一步的遗传筛选，我们找到了SPS的抑制基因SBOH2，建立了SnRK2-SPS-SBOH2的角质层调节路径。.本研究开启了ABA调节角质层的信号通路的研究，也为增加了我们对ABA的除了气孔和渗透胁迫作用之外的功能的了解，为通过角质层调节植物耐旱的实际应用提供理论基础和靶点基因。