Role of plant Ca2+-ATPase in calcium homeostasis during development and stresses

Calcium (Ca2+) is a ubiquitous signal and an essential macronutrient in plants. In response to extracellular stimuli, the spatiotemporal burst in cytosolic Ca2+ concentrations generates “Ca2+ signature,” which further decode the specific downstream signal transduction pathways. The Ca2+ efflux system, involves plant Ca2+-ATPases, plays important roles in fine tuning and termination of Ca2+ signature, which is essential for plant growth and survival. Plant Ca2+-ATPases, a family of the superfamily of P-type ATPase, are phylogenetically subgrouped as type-IIA/ER-type Ca2+-ATPase/ECAs and type-IIB/auto-inhibited Ca2+-ATPase/ACAs and are localized to different cellular membranes. Plant Ca2+-ATPases transport Ca2+ from the cytoplasm either into organelles or into the apoplast to maintain the differential Ca2+ concentrations in cellular compartments and thus are essential for Ca2+ homeostasis. Plant Ca2+-ATPases are also involved in many fundamental processes and in recent past, many studies have established their role in response to biotic and abiotic stresses, in vegetative growth and reproduction as well as in mineral nutrition and toxicity. Overall, this chapter covers the classification, structure, and regulation of Ca2+-ATPases and their established and emerging role of plant Ca2+-ATPases in plant growth and development as well as in response to biotic and abiotic stresses.