Mechanism and Evolution of Calcium Transport Across the Plant Plasma Membrane

Abstract

Calcium is an essential plant nutrient, thus the influx of Ca 2+ into plant cells is a critical process. In addition, the efflux of Ca 2+ out of a cell is important to prevent toxicity resulting from Ca 2+ excess, and to modulate levels of cytosolic Ca 2+ required for signaling functions. Biochemical and genetic analysis of plants has begun to identify the complement of Ca 2+ -permeable channels and Ca 2+ -ATPases that function in Ca 2+ flux across the plasma membrane. In addition to understanding the mechanisms of plasma membrane Ca 2+ transport, some of the specific functions of these pathways are now emerging. Comparative genomics of higher plant, algal and moss species has identified significant variation in the mechanisms of plasma membrane Ca 2+ transport between higher and lower plants, and provides insight into the evolution of Ca 2+ transport processes.