Mechanisms of calcium homeostasis orchestrate plant growth and immunity

• 成果类型: Article
• 署名作者: Wang, Chao; Tang, Ren-Jie; Kou, Senhao; Xu, Xiaoshu; Lu, Yi; Rauscher, Kenda; Voelker, Angela; Luan, Sheng
• 署名单位: University of California System; University of California Berkeley; Stanford University; University of California System; University of California Berkeley
• 刊物名称: Nature
• ISSN/ISSBN: 0028-4631
• DOI: 10.1038/s41586-024-07100-0
• 发表日期: 2024-03-14
• 关键词: salicylic-acid; gene; cax1; expression; atpases; channel; kinase; ca2+; activation; proteins

摘要

Calcium (Ca2+) is an essential nutrient for plants and a cellular signal, but excessive levels can be toxic and inhibit growth1,2. To thrive in dynamic environments, plants must monitor and maintain cytosolic Ca2+ homeostasis by regulating numerous Ca2+ transporters3. Here we report two signalling pathways in Arabidopsis thaliana that converge on the activation of vacuolar Ca2+/H+ exchangers (CAXs) to scavenge excess cytosolic Ca2+ in plants. One mechanism, activated in response to an elevated external Ca2+ level, entails calcineurin B-like (CBL) Ca2+ sensors and CBL-interacting protein kinases (CIPKs), which activate CAXs by phosphorylating a serine (S) cluster in the auto-inhibitory domain. The second pathway, triggered by molecular patterns associated with microorganisms, engages the immune receptor complex FLS2-BAK1 and the associated cytoplasmic kinases BIK1 and PBL1, which phosphorylate the same S-cluster in CAXs to modulate Ca2+ signals in immunity. These Ca2+-dependent (CBL-CIPK) and Ca2+-independent (FLS2-BAK1-BIK1/PBL1) mechanisms combine to balance plant growth and immunity by regulating cytosolic Ca2+ homeostasis. A study of calcium homeostasis in the plant Arabidopsis reveals two signalling pathways it uses to balance the objectives of growth and immunity by regulating the level of Ca2+ in the cytosol.