New insight into Ca²⁺‐permeable channel in plant immunity

Abstract

Calcium ions (Ca2+) are crucial intracellular second messengers in eukaryotic cells. Upon pathogen perception, plants generate a transient and rapid increase in cytoplasmic Ca2+ levels, which is subsequently decoded by Ca2+ sensors and effectors to activate downstream immune responses. The elevation of cytosolic Ca2+ is commonly attributed to Ca2+ influx mediated by plasma membrane‐localized Ca2+–permeable channels. However, the contribution of Ca2+ release triggered by intracellular Ca2+‐permeable channels in shaping Ca2+ signaling associated with plant immunity remains poorly understood. This review discusses recent advances in understanding the mechanism underlying the shaping of Ca2+ signatures upon the activation of immune receptors, with particular emphasis on the identification of intracellular immune receptors as non‐canonical Ca2+‐permeable channels. We also discuss the involvement of Ca2+ release from the endoplasmic reticulum in generating Ca2+ signaling during plant immunity.