Unraveling the molecular choreography of C 3 to CAM transition in Mesembryanthemum crystallinum using phosphoproteomics

作者：Bowen Tan, Noé Perron, Qijie Guan, Dan Zhu, Yatendra Singh, Craig Dufresne, Sixue Chen · 发表于：The Plant Journal · 年份：2025 · DOI：10.1111/tpj.70587 · 被引用次数：3 · 研究领域：Photosynthetic Processes and Mechanisms、Plant Stress Responses and Tolerance、Plant responses to water stress

SUMMARY Climate change and population growth threaten global freshwater resources and food security. Crassulacean acid metabolism (CAM) is a specialized photosynthetic adaptation that exhibits superior water use efficiency (WUE) compared to C 3 and C 4 photosynthesis. Mesembryanthemum crystallinum (common ice plant) is capable of shifting from C 3 to CAM, making it a key model for investigating photosynthesis plasticity and its potential to enhance crop stress resilience. To date, the molecular mechanisms underlying this high‐WUE photosynthetic transition remain largely unknown. Using mass spectrometry‐based proteomics and phosphoproteomics, we quantified 4233 phosphopeptides containing 4758 phosphorylation sites, including the well‐characterized Serine 11 of phosphoenolpyruvate carboxylase 1 (PEPC1). It is a critical phosphorylation site facilitating nocturnal CO 2 fixation during CAM. Our analysis revealed many phosphorylation sites that exhibited similar diel patterns as the PEPC1 pS11, and they may be part of the regulatory network involved in CAM induction. Glycolysis/gluconeogenesis and carbon storage/breakdown modules exhibited extensive phosphorylation regulation, and vesicle trafficking could play a role in nocturnal carbon fixation. Furthermore, glycine‐rich RNA‐binding protein 7 (GRP7) in association with cold shock protein 1 (CSP1) emerged as a potential transcriptional switch for nocturnal stomatal opening. On the other hand, ABI5‐binding protein 1 (AFP1) and oxi...