Key Laboratory of Horticultural Plant Biology, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Sciences and Technology, Huazhong Agricultural University, Wuhan,430070, China.
Plant Sci. 2020 Feb;291:110320. doi: 10.1016/j.plantsci.2019.110320. Epub 2019 Nov 9.
Calcium-dependent protein kinases (CDPKs) are important calcium signaling components that have been shown to play crucial roles in modulating plant abiotic stress responses. However, the physiological and regulatory roles of most CDPKs are still poorly understood. Here, we report the functional characterization of PtrCDPK10 from trifoliate orange (Poncirus trifoliata (L.) Raf.) in dehydration and drought stress tolerance. PtrCDPK10, categorized in the Type III subgroup of the CDPK family, was localized to the nucleus and plasma membrane. Transcript levels of PtrCDPK10 were up-regulated by dehydration, salt and ABA treatments. Transgenic trifoliate orange plants overexpressing PtrCDPK10 showed enhanced dehydration tolerance compared with the wild type (WT), whereas VIGS (virus-induced gene silencing)-mediated knockdown of PtrCDPK10 resulted in elevated susceptibility to dehydration and drought stresses. Yeast two-hybrid screening identified several proteins that interacted with PtrCDPK10, including an ascorbate peroxidase (PtrAPX). PtrCDPK10 was shown to phosphorylate PtrAPX based on an in vitro kinase assay. PtrCDPK10-overexpressing transgenic lines exhibited higher PtrAPX mRNA abundance and APX activity and accumulated dramatically less ROS in comparison with the WT, while PtrCDPK10-silenced VIGS lines showed decreased PtrAPX expression and increased ROS level. Taken together, these results demonstrate that PtrCDPK10 promotes dehydration and drought tolerance by, at least in part, phosphorylating APX to modulate ROS homeostasis.
钙依赖蛋白激酶（CDPKs）是重要的钙信号成分，已被证明在调节植物非生物胁迫反应中发挥关键作用。然而，大多数 CDPK 的生理和调节作用仍知之甚少。在这里，我们报告了来自枳（Poncirus trifoliata（L.）Raf.）的 PtrCDPK10 在脱水和干旱胁迫耐受性中的功能特征。PtrCDPK10 被归类为 CDPK 家族的 III 型亚组，定位于细胞核和质膜。脱水、盐和 ABA 处理上调 PtrCDPK10 的转录水平。过表达 PtrCDPK10 的转基因枳植物表现出比野生型（WT）更强的脱水耐受性，而 VIGS（病毒诱导的基因沉默）介导的 PtrCDPK10 敲低导致对脱水和干旱胁迫的敏感性增加。酵母双杂交筛选鉴定出与 PtrCDPK10 相互作用的几种蛋白质，包括抗坏血酸过氧化物酶（PtrAPX）。根据体外激酶测定，PtrCDPK10 被证明可磷酸化 PtrAPX。与 WT 相比，PtrCDPK10 过表达的转基因株系表现出更高的 PtrAPX mRNA 丰度和 APX 活性，并且 ROS 积累显著减少，而 PtrCDPK10 沉默的 VIGS 株系表现出 PtrAPX 表达降低和 ROS 水平升高。总之，这些结果表明 PtrCDPK10 通过至少部分地磷酸化 APX 来调节 ROS 稳态，从而促进脱水和干旱耐受性。
