National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Plant J. 2012 Jan;69(1):26-36. doi: 10.1111/j.1365-313X.2011.04766.x. Epub 2011 Oct 10.
Calcium-dependent protein kinases (CDPKs) regulate the downstream components in calcium signaling pathways. We investigated the effects of overexpression and disruption of an Oryza sativa (rice) CDPK (OsCPK12) on the plant's response to abiotic and biotic stresses. OsCPK12-overexpressing (OsCPK12-OX) plants exhibited increased tolerance to salt stress. The accumulation of hydrogen peroxide (H(2) O(2) ) in the leaves was less in OsCPK12-OX plants than in wild-type (WT) plants. Genes encoding reactive oxygen species (ROS) scavenging enzymes (OsAPx2 and OsAPx8) were more highly expressed in OsCPK12-OX plants than in WT plants, whereas the expression of the NADPH oxidase gene, OsrbohI, was decreased in OsCPK12-OX plants compared with WT plants. Conversely, a retrotransposon (Tos17) insertion mutant, oscpk12, and plants transformed with an OsCPK12 RNA interference (RNAi) construct were more sensitive to high salinity than were WT plants. The level of H(2) O(2) accumulation was greater in oscpk12 and OsCPK12 RNAi plants than in the WT. These results suggest that OsCPK12 promotes tolerance to salt stress by reducing the accumulation of ROS. We also observed that OsCPK12-OX seedlings had increased sensitivity to abscisic acid (ABA) and increased susceptibility to blast fungus, probably resulting from the repression of ROS production and/or the involvement of OsCPK12 in the ABA signaling pathway. Collectively, our results suggest that OsCPK12 functions in multiple signaling pathways, positively regulating salt tolerance and negatively modulating blast resistance.
钙依赖蛋白激酶（CDPKs）调节钙信号通路中的下游成分。我们研究了过量表达和敲除一种水稻（Oryza sativa）CDPK（OsCPK12）对植物应对非生物和生物胁迫的影响。OsCPK12 过表达（OsCPK12-OX）植物表现出对盐胁迫的耐受性增加。OsCPK12-OX 植物叶片中过氧化氢（H₂O₂）的积累比野生型（WT）植物少。编码活性氧（ROS）清除酶（OsAPx2 和 OsAPx8）的基因在 OsCPK12-OX 植物中的表达高于 WT 植物，而 NADPH 氧化酶基因 OsrbohI 的表达在 OsCPK12-OX 植物中比 WT 植物减少。相反，反转录转座子（Tos17）插入突变体 oscpk12 和用 OsCPK12 RNA 干扰（RNAi）构建体转化的植物对高盐度比 WT 植物更敏感。H₂O₂积累水平在 oscpk12 和 OsCPK12 RNAi 植物中比 WT 植物更高。这些结果表明，OsCPK12 通过减少 ROS 的积累促进了对盐胁迫的耐受性。我们还观察到 OsCPK12-OX 幼苗对脱落酸（ABA）的敏感性增加，对炭疽病真菌的易感性增加，这可能是由于 ROS 产生的抑制和/或 OsCPK12 参与了 ABA 信号通路。总的来说，我们的结果表明 OsCPK12 在多个信号通路中发挥作用，正向调节盐耐受性，负向调节对炭疽病的抗性。
