State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, National Plant Gene Research Center, China Agricultural University, Beijing, China.
Plant Physiol. 2010 Nov;154(3):1232-43. doi: 10.1104/pp.110.157545. Epub 2010 Aug 30.
Plant calcium-dependent protein kinases (CDPKs) may function as calcium sensors and play important roles in the regulation of plant growth and development and in plant responses to biotic and abiotic stresses. The Arabidopsis (Arabidopsis thaliana) genome encodes 34 CDPKs, and most of them have not been functionally characterized. Here, we report the functional characterization of CPK10 in Arabidopsis response to drought stress. The cpk10 mutant, a T-DNA insertion mutant for the Arabidopsis CPK10 gene, showed a much more sensitive phenotype to drought stress compared with wild-type plants, while the CPK10 overexpression lines displayed enhanced tolerance to drought stress. Induction of stomatal closure and inhibition of stomatal opening by abscisic acid (ABA) and Ca(2+) were impaired in the cpk10 mutants. Using yeast two-hybrid methods, a heat shock protein, HSP1, was identified as a CPK10-interacting protein. The interaction between CPK10 and HSP1 was further confirmed by pull-down and bimolecular fluorescence complementation assays. The HSP1 knockout mutant (hsp1) plants showed a similar sensitive phenotype under drought stress as the cpk10 mutant plants and were similarly less sensitive to ABA and Ca(2+) in regulation of stomatal movements. Electrophysiological experiments showed that ABA and Ca(2+) inhibition of the inward K(+) currents in stomatal guard cells were impaired in the cpk10 and hsp1 mutants. All presented data demonstrate that CPK10, possibly by interacting with HSP1, plays important roles in ABA- and Ca(2+)-mediated regulation of stomatal movements.
植物钙依赖型蛋白激酶（CDPKs）可能作为钙传感器发挥作用，在调节植物生长发育以及植物对生物和非生物胁迫的响应中发挥重要作用。拟南芥（Arabidopsis thaliana）基因组编码 34 种 CDPKs，其中大多数尚未进行功能表征。在这里，我们报告了拟南芥对干旱胁迫反应中 CPK10 的功能特征。与野生型植物相比，CPK10 的 T-DNA 插入突变体 cpk10 对干旱胁迫表现出更为敏感的表型，而 CPK10 过表达系表现出增强的耐旱性。拟南芥 cpk10 突变体中，ABA 和 Ca2+诱导的气孔关闭和抑制气孔开放的能力受损。利用酵母双杂交方法，鉴定到一种热休克蛋白 HSP1 是 CPK10 的互作蛋白。CPK10 和 HSP1 之间的相互作用通过下拉和双分子荧光互补实验进一步证实。HSP1 敲除突变体（hsp1）在干旱胁迫下表现出与 cpk10 突变体相似的敏感表型，并且在调节气孔运动对 ABA 和 Ca2+的敏感性方面也相似。电生理实验表明，ABA 和 Ca2+抑制气孔保卫细胞内向 K+电流的能力在 cpk10 和 hsp1 突变体中受损。所有呈现的数据表明，CPK10 可能通过与 HSP1 相互作用，在 ABA 和 Ca2+介导的气孔运动调节中发挥重要作用。
