College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
Institute of Food Crops, Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
New Phytol. 2021 Jul;231(2):695-712. doi: 10.1111/nph.17403. Epub 2021 May 17.
Drought stress seriously limits crop productivity. Although studies have been carried out, it is still largely unknown how plants respond to drought stress. Here we find that drought treatment can enhance the phosphorylation activity of brassinosteroid-signaling kinase 1 (ZmBSK1) in maize (Zea mays). Our genetic studies reveal that ZmBSK1 positively affects drought tolerance in maize plants. ZmBSK1 localizes in plasma membrane, interacts with calcium/calmodulin (Ca /CaM)-dependent protein kinase (ZmCCaMK), and phosphorylates ZmCCaMK. Ser-67 is a crucial phosphorylation site of ZmCCaMK by ZmBSK1. Drought stress enhances not only the interaction between ZmBSK1 and ZmCCaMK but also the phosphorylation of Ser-67 in ZmCCaMK by ZmBSK1. Furthermore, Ser-67 phosphorylation in ZmCCaMK regulates its Ca /CaM binding, autophosphorylation and transphosphorylation activity, and positively affects its function in drought tolerance in maize. Our results reveal an important role for ZmBSK1 in drought tolerance and suggest a direct regulatory mode of ZmBSK1 phosphorylating ZmCCaMK.
干旱胁迫严重限制了作物的生产力。尽管已经开展了相关研究，但植物如何应对干旱胁迫在很大程度上仍不清楚。在这里，我们发现干旱处理可以增强玉米（Zea mays）中油菜素类固醇信号激酶 1（ZmBSK1）的磷酸化活性。我们的遗传研究表明，ZmBSK1 正向影响玉米植物的耐旱性。ZmBSK1 定位于质膜上，与钙/钙调蛋白（Ca/CaM）依赖性蛋白激酶（ZmCCaMK）相互作用，并磷酸化 ZmCCaMK。Ser-67 是 ZmBSK1 磷酸化 ZmCCaMK 的关键磷酸化位点。干旱胁迫不仅增强了 ZmBSK1 和 ZmCCaMK 之间的相互作用，还增强了 ZmBSK1 对 ZmCCaMK 中 Ser-67 的磷酸化作用。此外，ZmCCaMK 中的 Ser-67 磷酸化调节其与 Ca/CaM 的结合、自身磷酸化和转磷酸化活性，并正向影响其在玉米耐旱性中的功能。我们的研究结果揭示了 ZmBSK1 在耐旱性中的重要作用，并提出了 ZmBSK1 磷酸化 ZmCCaMK 的直接调控模式。
