State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, Northwest A & F University, Yangling, Shaanxi 712100, People's Republic of China.
College of Plant Protection, Henan Agricultural University, Zhengzhou 450002, Henan Province, People's Republic of China.
J Agric Food Chem. 2024 Jun 5;72(22):12445-12458. doi: 10.1021/acs.jafc.4c00385. Epub 2024 May 21.
Global water deficit is a severe abiotic stress threatening the yielding and quality of crops. Abscisic acid (ABA) is a phytohormone that mediates drought tolerance. Protein kinases and phosphatases function as molecular switches in eukaryotes. Protein phosphatases type 2C (PP2Cs) are a major family that play essential roles in ABA signaling and stress responses. However, the role and underlying mechanism of PP2C in rapeseed ( L.) mediating drought response has not been reported yet. Here, we characterized a PP2C family member, BnaPP2C37, and its expression level was highly induced by ABA and dehydration treatments. It negatively regulates drought tolerance in rapeseed. We further identified that BnaPP2C37 interacted with multiple PYR/PYL receptors and a drought regulator BnaCPK5 (calcium-dependent protein kinase 5) through yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. Specifically, BnaPYL1 and BnaPYL9 repress BnaPP2C37 phosphatase activity. Moreover, the pull-down assay and phosphatase assays show BnaPP2C37 interacts with BnaCPK5 to dephosphorylate BnaCPK5 and its downstream BnaABF3. Furthermore, a dual-luciferase assay revealed transcript level was enhanced by BnaABF3 and BnaABF4, forming a negative feedback regulation to ABA response. In summary, we identified that BnaPP2C37 functions negatively in drought tolerance of rapeseed, and its phosphatase activity is repressed by BnaPYL1/9 whereas its transcriptional level is upregulated by BnaABF3/4.
全球水资源短缺是一种严重的非生物胁迫，威胁着作物的产量和品质。脱落酸（ABA）是一种介导植物耐旱性的植物激素。蛋白激酶和磷酸酶在真核生物中作为分子开关发挥作用。蛋白磷酸酶 2C 型（PP2Cs）是一个主要家族，在 ABA 信号转导和应激反应中发挥重要作用。然而，PP2C 在油菜（ L.）中介导干旱响应的作用及其潜在机制尚未报道。在这里，我们鉴定了一个 PP2C 家族成员 BnaPP2C37，其表达水平被 ABA 和脱水处理高度诱导。它负调控油菜的耐旱性。我们进一步发现 BnaPP2C37 通过酵母双杂交（Y2H）和双分子荧光互补（BiFC）实验与多个 PYR/PYL 受体和一个干旱调节剂 BnaCPK5（钙依赖性蛋白激酶 5）相互作用。具体来说，BnaPYL1 和 BnaPYL9 抑制 BnaPP2C37 的磷酸酶活性。此外，下拉实验和磷酸酶实验表明 BnaPP2C37 与 BnaCPK5 相互作用，使 BnaCPK5 及其下游的 BnaABF3 去磷酸化。此外，双荧光素酶实验表明转录水平被 BnaABF3 和 BnaABF4 增强，形成对 ABA 反应的负反馈调节。综上所述，我们发现 BnaPP2C37 在油菜的耐旱性中起负调控作用，其磷酸酶活性受 BnaPYL1/9 抑制，而其转录水平受 BnaABF3/4 上调。
