College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China; Department of Biology, Genetics Institute, Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32610, USA.
Department of Biology, Genetics Institute, Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32610, USA; Guangdong Province Key Laboratory for Plant Epigenetics, College of Life Science and Oceanography, Shenzhen University, 518060 Shenzhen, China.
J Proteomics. 2021 Jan 16;231:104019. doi: 10.1016/j.jprot.2020.104019. Epub 2020 Oct 16.
Salinity can induce Mesembryanthemum crystallinum to shift its photosynthesis from C to crassulacean acid metabolism (CAM), leading to enhanced plant water use efficiency. Studying how M. crystallinum changes its carbon fixation pathways is important for potential translation into crops and enhancing crop resilience. In this study, we examined proteomic changes in guard cells and mesophyll cells in the course of the C to CAM transition. We collected enriched guard cells and mesophyll cells during a short period of transition. A total of 1153 proteins were identified and quantified in the two cell-types. During the transition, proteins in the guard cells and mesophyll cells exhibited differential changes. For example, we observed nocturnal carbon fixation in mesophyll cells and proteins involved in cell growth in the two cell-types. Proteins involved in osmotic adjustment, ion transport, energy metabolism and light response may play important roles in the C to CAM transition. Real-time PCR experiments were conducted to determine potential correlations between transcript and protein levels. These results have highlighted potential molecular mechanisms underlying the C to CAM transition of guard cells and mesophyll cells of the important facultative CAM plant. BIOLOGICAL SIGNIFICANCE: Fresh water resource for agricultural food production is a global challenge. Nature has evolved crassulacean acid metabolism (CAM) plants with enhanced water use efficiency. Using single cell-type proteomics, this study revealed molecular changes taking place in guard cells and mesophyll cells during the shift of ice plant photosynthesis from C3 to CAM. The results have provided important insights into the CAM transition and may facilitate effort toward enhancing crop resilience for global food security.
盐度可以诱导马齿苋（Mesembryanthemum crystallinum）将其光合作用从 C 途径转变为景天酸代谢（CAM）途径，从而提高植物的水分利用效率。研究马齿苋如何改变其碳固定途径对于潜在的作物转化和提高作物的抗逆性具有重要意义。在本研究中，我们研究了 C 途径到 CAM 途径转变过程中保卫细胞和叶肉细胞的蛋白质组变化。我们在短时间的转变过程中收集了富含保卫细胞和叶肉细胞的样本。在这两种细胞类型中鉴定和定量了总共 1153 种蛋白质。在转变过程中，保卫细胞和叶肉细胞中的蛋白质表现出不同的变化。例如，我们观察到叶肉细胞在夜间进行碳固定，以及两种细胞类型中与细胞生长相关的蛋白质。参与渗透调节、离子转运、能量代谢和光反应的蛋白质可能在 C 途径到 CAM 途径的转变中发挥重要作用。实时 PCR 实验用于确定转录物和蛋白质水平之间的潜在相关性。这些结果突出了重要的兼性 CAM 植物保卫细胞和叶肉细胞从 C 途径到 CAM 途径转变的潜在分子机制。生物学意义：农业食品生产的淡水资源是一个全球性挑战。自然界已经进化出景天酸代谢（CAM）植物，它们具有更高的水分利用效率。本研究使用单细胞蛋白质组学技术，揭示了冰叶日中花光合作用从 C3 途径转变为 CAM 途径过程中保卫细胞和叶肉细胞中发生的分子变化。研究结果为 CAM 转变提供了重要的见解，并可能有助于提高全球粮食安全作物的抗逆性。
