WeiTsing: a new face of Ca(2+)-permeable channels in plant immunity

Plants employ pattern- and effector-triggered immunity (PTI and ETI) to synergistically defend invading pathogens and insect herbivores. Both PTI and ETI can induce cytosolic Ca(2+) spikes, despite in different spatiotemporal patterns, to activate downstream Ca(2+)-dependent immune signaling cascades. While multiple families of Ca(2+)-permeable channels at the plasma membrane have been uncovered, the counterparts responsible for Ca(2+) release from intracellular stores remain poorly understood. In a groundbreaking paper published recently by Cell, the authors reported that WeiTsing, an Arabidopsis endoplasmic reticulum (ER)-resident protein that was specifically expressed in the pericycle upon Plasmodiophora brassicae (Pb) infection, could form resistosome-like Ca(2+)-conducting channel and protect the stele of Brassica crops from Pb colonization. As the channel activity of WeiTsing was indispensable for its immune function, the findings highlight a previously underappreciated role of Ca(2+) release from intracellular repertoire in promoting plant disease resistance.