College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China.
Plant Physiol. 2022 Sep 28;190(2):1321-1333. doi: 10.1093/plphys/kiac311.
Calmodulin-like proteins (CMLs) are calcium (Ca2+) sensors involved in plant growth and development as well as adaptation to environmental stresses; however, their roles in plant responses to cold are not well understood. To reveal the role of MsCML10 from alfalfa (Medicago sativa) in regulating cold tolerance, we examined transgenic alfalfa and Medicago truncatula overexpressing MsCML10, MsCML10-RNAi alfalfa, and a M. truncatula cml10-1 mutant and identified MsCML10-interacting proteins. MsCML10 and MtCML10 transcripts were induced by cold treatment. Upregulation or downregulation of MsCML10 resulted in increased or decreased cold tolerance, respectively, while cml10-1 showed decreased cold tolerance that was complemented by expressing MsCML10, suggesting that MsCML10 regulates cold tolerance. MsCML10 interacted with glutathione S-transferase (MsGSTU8) and fructose 1,6-biphosphate aldolase (MsFBA6), and the interaction depended on the presence of Ca2+. The altered activities of Glutathione S-transferase and FBA and levels of ROS and sugars were associated with MsCML10 transcript levels. We propose that MsCML10 decodes the cold-induced Ca2+ signal and regulates cold tolerance through activating MsGSTU8 and MsFBA6, leading to improved maintenance of ROS homeostasis and increased accumulation of sugars for osmoregulation, respectively.
钙调素样蛋白（CMLs）是参与植物生长发育以及适应环境胁迫的钙离子（Ca2+）传感器；然而，它们在植物对寒冷响应中的作用尚不清楚。为了揭示紫花苜蓿（Medicago sativa）中 MsCML10 蛋白在调节耐冷性中的作用，我们对过表达 MsCML10、MsCML10-RNAi 苜蓿和 M. truncatula cml10-1 突变体的转基因苜蓿和 M. truncatula 进行了研究，并鉴定了 MsCML10 相互作用蛋白。MsCML10 和 MtCML10 转录本受冷处理诱导。MsCML10 的上调或下调分别导致冷耐性增加或降低，而 cml10-1 表现出降低的冷耐性，通过表达 MsCML10 得到了互补，表明 MsCML10 调节冷耐性。MsCML10 与谷胱甘肽 S-转移酶（MsGSTU8）和果糖 1,6-二磷酸醛缩酶（MsFBA6）相互作用，这种相互作用依赖于 Ca2+的存在。谷胱甘肽 S-转移酶和 FBA 的活性改变以及 ROS 和糖的水平与 MsCML10 转录本水平相关。我们提出 MsCML10 解码冷诱导的 Ca2+信号，并通过激活 MsGSTU8 和 MsFBA6 来调节冷耐性，从而分别导致 ROS 动态平衡的改善和糖的积累增加以进行渗透调节。
