Plant autoinhibited Ca2+-ATPases: shaping calcium signals for growth, stress adaptation, and crop improvement

P-type ATPases are conserved ATP-driven ion transporters that maintain cellular ion homeostasis. Plant P-type IIB Ca 2+ -ATPases, known as autoinhibited Ca 2+ -ATPases (ACAs), are key regulators of Ca 2+ signaling networks. This review summarizes the structural features, Ca 2+ /calmodulin-dependent regulation, evolutionary diversification, and biological functions of plant ACAs. By contributing to cytosolic Ca 2+ clearance and the restoration of basal Ca 2+ levels, ACAs may modulate stimulus-specific Ca 2+ dynamics and participate in diverse physiological processes, including plant growth, development, stomatal movement, immunity, and abiotic stress adaptation. Comparative analyses across plant species highlight functional specialization of ACA isoforms and their potential value for crop improvement. We further discuss current challenges in ACA functional characterization, particularly the complexity of Ca 2+ signaling networks and the limited understanding of ACA-associated genetic variation. Emerging approaches integrating multi-omics, artificial intelligence, and precision genome editing provide new opportunities for identifying and designing ACA alleles for climate-resilient crop breeding.