Abstract The cytosolic Ca2+ ([Ca2+]cyt), in plants serves as secondary messenger during development and stress adaptive responses. While several of the components of Ca2+-signalling, especially involved in water-deficit stress or dehydration are known, the underlying mechanism of such regulations remain poorly understood. In this study, we investigated the Ca2+-mediated alleviation of dehydration stress in rice. The physicochemical indices of the rice seedlings pretreated with CaCl2, followed by dehydration treatment displayed better maintenance of relative water content (RWC) and cell membrane integrity, besides peroxide levels. CaCl2-pretreated seedling showed stimulation of antioxidants contributing to long-term survival under dehydration stress. Contrastingly, blocking of Ca2+-channels aggravated the dehydration-induced damage, suggesting a crucial role of Ca2+-signalling in stress adaptation. The cytosolic proteome profiling of CaCl2-pretreated seedlings revealed 100 distinct proteins that include 56 dehydration-responsive proteins (DRPs), presumably involved in adaptive responses. A critical screening of the proteome led to the identification of a MADS-box transcription factor family protein, designated OsMADS23. The predicted structure and nuclear localization indicated that OsMADS23 might bind to nucleic acids, suggesting its possible role in transcriptional regulation. The stimulation of stress-responsive expression of OsMADS23 by Ca2+ demonstrated its participation in Ca2+-dependent signalling. Altogether, these results indicate the Ca2+-dependent dehydration response in plants and substantiate the function of a MADS-box protein in the cross-talk of developmental and stress-responsive pathways.

中文翻译：

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物理化学性质和蛋白质组动力学的钙依赖性变化影响水稻的脱水反应

摘要 植物体内的细胞质 Ca2+ ([Ca2+]cyt) 在发育和逆境适应性反应过程中充当二级信使。虽然已知 Ca2+ 信号的几个组成部分，特别是与缺水压力或脱水有关的成分，但此类调节的潜在机制仍知之甚少。在这项研究中，我们研究了 Ca2+ 介导的水稻脱水胁迫缓解。除过氧化物水平外，用 CaCl2 预处理然后脱水处理的水稻幼苗的理化指标显示出更好的相对含水量 (RWC) 和细胞膜完整性的维持。CaCl2 预处理的幼苗显示出抗氧化剂的刺激作用，有助于在脱水胁迫下长期存活。相比之下，Ca2+ 通道的阻塞加剧了脱水引起的损伤，表明 Ca2+ 信号在压力适应中的关键作用。CaCl2 预处理幼苗的细胞溶质蛋白质组分析揭示了 100 种不同的蛋白质，其中包括 56 种脱水反应蛋白 (DRP)，可能与适应性反应有关。蛋白质组的关键筛选导致 MADS-box 转录因子家族蛋白的鉴定，命名为 OsMADS23。预测的结构和核定位表明 OsMADS23 可能与核酸结合，表明其可能在转录调控中发挥作用。Ca2+ 对 OsMADS23 应激反应性表达的刺激表明其参与 Ca2+ 依赖性信号传导。共，