College of Agriculture/The Key Laboratory of Oasis Eco-agriculture, Shihezi University, Shihezi, 832000, Xinjiang, China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China.
Plant J. 2023 Jun;114(6):1405-1424. doi: 10.1111/tpj.16200. Epub 2023 Apr 8.
Protein lysine acetylation is an important post-translational modification mechanism involved in cellular regulation in eukaryotes. Calmodulin (CaM) is a ubiquitous Ca sensor in eukaryotes and is crucial for plant immunity, but it is so far unclear whether acetylation is involved in CaM-mediated plant immunity. Here, we found that GhCaM7 is acetylated upon Verticillium dahliae (V. dahliae) infection and a positive regulator of V. dahliae resistance. Overexpressing GhCaM7 in cotton and Arabidopsis enhances V. dahliae resistance and knocking-down GhCaM7 makes cotton more susceptible to V. dahliae. Transgenic Arabidopsis plants overexpressing GhCaM7 with mutation at the acetylation site are more susceptible to V. dahliae than transgenics overexpressing the wild-type GhCaM7, implying the importance of the acetylated GhCaM7 in response to V. dahliae infection. Yeast two-hybrid, bimolecular fluorescent complementation, luciferase complementation imaging, and coimmunoprecipitation assays demonstrated interaction between GhCaM7 and an osmotin protein GhOSM34 that was shown to have a positive role in V. dahliae resistance. GhCaM7 and GhOSM34 are co-localized in the cell membrane. Upon V. dahliae infection, the Ca content reduces almost instantly in plants with downregulated GhCaM7 or GhOSM34. Down regulating GhOSM34 enhances accumulation of Na and increases cell osmotic pressure. Comparative transcriptomic analyses between cotton plants with an increased or reduced expression level of GhCaM7 and wild-type plants indicate the involvement of jasmonic acid signaling pathways and reactive oxygen species in GhCaM7-enabled disease resistance. Together, these results demonstrate the involvement of CaM protein in the interaction between cotton and V. dahliae, and more importantly, the involvement of the acetylated CaM in the interaction.
蛋白赖氨酸乙酰化是真核细胞中细胞调节的一种重要的翻译后修饰机制。钙调蛋白（CaM）是真核生物中普遍存在的 Ca 传感器，对植物免疫至关重要，但目前尚不清楚乙酰化是否参与 CaM 介导的植物免疫。在这里，我们发现，在黄萎病菌（V. dahliae）感染时GhCaM7 发生乙酰化，是 V. dahliae 抗性的正调控因子。在棉花和拟南芥中过表达 GhCaM7 增强了对 V. dahliae 的抗性，而敲低 GhCaM7 则使棉花更容易感染 V. dahliae。与过表达野生型 GhCaM7 的转基因拟南芥相比，过表达乙酰化位点突变的 GhCaM7 的转基因拟南芥对 V. dahliae 更敏感，这表明乙酰化 GhCaM7 在应对 V. dahliae 感染中的重要性。酵母双杂交、双分子荧光互补、荧光素酶互补成像和免疫共沉淀实验表明 GhCaM7 与 osmotin 蛋白 GhOSM34 相互作用，GhOSM34 在 V. dahliae 抗性中起积极作用。GhCaM7 和 GhOSM34 共定位于细胞膜上。在 V. dahliae 感染后，下调 GhCaM7 或 GhOSM34 的植株中 Ca 含量几乎立即降低。下调 GhOSM34 会增加 Na 的积累并增加细胞渗透压。增加或降低 GhCaM7 表达水平的棉花植株与野生型植株之间的比较转录组分析表明，茉莉酸信号通路和活性氧参与了 GhCaM7 介导的抗病性。综上所述，这些结果表明钙调蛋白蛋白参与了棉花与黄萎病菌的互作，更重要的是，参与了乙酰化钙调蛋白的互作。
