Cellular and Molecular Mechanisms for Elevated CO2-Regulation of Plant Growth and Stress Adaptation

Increases in atmospheric CO2 concentration have exerted significant impacts on plant growth. Numerous studies have reported positive effects of elevated CO2 on plant growth and adaptation to various environmental stresses in many plant species. The mechanisms by which CO2 enrichment regulates plant growth and stress adaptation are not completely understood. There have been some recent exciting advances in elucidating the cellular, metabolic, and molecular basis for increased growth under elevated CO2. At the cellular level, cell growth involving both cell division and cell expansion is stimulated by increasing CO2, which has been associated with increased photosynthetic activities and carbohydrate availability, and also with the expression of genes controlling cell division, cycling, and cell expansion. Proteomic profiling studies identified CO2-regulated proteins mainly involved in photosynthesis, carbon metabolism, energy pathways, molecular chaperones, and antioxidant proteins. Transcriptomic analyses identified several hundreds of genes responsive to elevated CO2 levels, which play roles in cell wall loosening, photosynthesis, respiration, water use, and protein synthesis, as well as stress defense. This paper reviews recent progress in the mechanistic understanding of CO2 regulation of plant growth and stress adaptation at the cellular, metabolic, and molecular levels, and addresses research gaps and future research perspective areas.