Wang Xianling, Wang Yu, Wang Lu, Liu Huan, Zhang Bing, Cao Qijiang, Liu Xinyu, Lv Yanling, Bi Shuangtian, Zhang Shaobin, He Ming, Tang Shuang, Yao Shuo, Wang Che
College of Biological Science and Biotechnology, Shenyang Agricultural University, Shenyang, China.
Department of Medicine, HE University School of Clinical Medicine, Shenyang, China.
Front Plant Sci. 2018 May 8;9:578. doi: 10.3389/fpls.2018.00578. eCollection 2018.
Water stress has a major influence on plant growth, development, and productivity. However, the cross-talk networks involved in drought tolerance are not well understood. Arabidopsis PCaP2 is a plasma membrane-associated Ca-binding protein. In this study, we employ qRT-PCR and β-glucuronidase (GUS) histochemical staining to demonstrate that expression was strongly induced in roots, cotyledons, true leaves, lateral roots, and whole plants under water deficit conditions. Compared with the wild type (WT) plants, -overexpressing (-OE) plants displayed enhanced water deficit tolerance in terms of seed germination, seedling growth, and plant survival status. On the contrary, mutation and reduction via -RNAi rendered plants more sensitive to water deficit. Furthermore, -RNAi and seedlings showed shorter root hairs and lower relative water content compared to WT under normal conditions and these phenotypes were exacerbated under water deficit. Additionally, the expression of was strongly induced by exogenous abscisic acid (ABA) and salicylic acid (SA) treatments. -OE plants showed insensitive to exogenous ABA and SA treatments, in contrast to the susceptible phenotypes of and -RNAi. It is well-known that SNF1-related kinase 2s (SnRK2s) and pathogenesis-related (PRs) are major factors that influence plant drought tolerance by ABA- and SA-mediated pathways, respectively. Interestingly, PCaP2 positively regulated the expression of drought-inducible genes (, , and ), ABA-mediated drought responsive genes (, , , , , , ), and SA-mediated drought responsive genes (, , ) under water deficit, ABA, or SA treatments. Taken together, our results showed that PCaP2 plays an important and positive role in Arabidopsis water deficit tolerance by involving in response to both ABA and SA signals and regulating root hair growth. This study provides novel insights into the underlying cross-talk mechanisms of plants in response to water deficit stress.
水分胁迫对植物的生长、发育和生产力有重大影响。然而，参与耐旱性的相互作用网络尚未得到充分了解。拟南芥PCaP2是一种与质膜相关的钙结合蛋白。在本研究中，我们采用qRT-PCR和β-葡萄糖醛酸酶（GUS）组织化学染色来证明，在水分亏缺条件下，其在根、子叶、真叶、侧根和整株植物中表达强烈诱导。与野生型（WT）植株相比，过表达（-OE）植株在种子萌发、幼苗生长和植株存活状态方面表现出增强的水分亏缺耐受性。相反，通过-RNAi进行突变和降低使植株对水分亏缺更敏感。此外，与正常条件下的WT相比，-RNAi和幼苗的根毛较短，相对含水量较低，并且在水分亏缺条件下这些表型会加剧。此外，外源脱落酸（ABA）和水杨酸（SA）处理强烈诱导了的表达。与和-RNAi的敏感表型相反，-OE植株对外源ABA和SA处理不敏感。众所周知，SNF1相关激酶2（SnRK2）和病程相关蛋白（PR）分别是通过ABA和SA介导的途径影响植物耐旱性的主要因素。有趣的是，在水分亏缺、ABA或SA处理下，PCaP2正向调节干旱诱导基因（、、）、ABA介导的干旱响应基因（、、、、、、）和SA介导的干旱响应基因（、、）的表达。综上所述，我们的结果表明，PCaP2通过参与ABA和SA信号响应并调节根毛生长，在拟南芥水分亏缺耐受性中发挥重要的正向作用。本研究为植物响应水分亏缺胁迫的潜在相互作用机制提供了新的见解。
