Rising Star: A Unified Mechanism of Plant NLR Immune Signaling

Jijie Chai earned his Ph.D. in analytical chemistry from the Institute of Materia Medica, Chinese Academy of Medical Sciences, and conducted postdoctoral research at Princeton University. In 2004, he established his independent research group at National Institute of Biological Science (China), focusing on plant immune receptors, particularly nucleotide-binding leucine-rich repeat (NLR) proteins. NLRs are the largest family immune receptors that enable plants to detect a wide array of pathogen effectors and activate effector-triggered immunity (ETI). Despite their recognition diversity, they elicit remarkably conserved immune responses, a mechanistic puzzle for many years. Chai's team achieved a landmark breakthrough by reconstituting and solving the cryo-EM structure of activated Arabidopsis coiled-coil NLR (CNL) ZAR1, revealing its assembly into a pentameric resistosome. The N-terminal helices of ZAR1 in the resistosome form a funnel-like structure, which was later confirmed as a Ca²⁺-permeable ion channel. These discoveries directly link NLR activation to Ca²⁺ influx, a central immune signaling event. Chai's findings further showed that CNLs form structurally conserved resistosomes with intrinsic Ca2⁺-permeable channel activity. Notably, Chai discovered that TIR-domain NLRs (TNLs) also form resistosomes but function as NADases, producing small-molecule signals that activate downstream helper NLRs. These helper NLRs also assemble into Ca²⁺-conducting resistosomes. Together, these findings establish a unified mechanism in plant immunity, with diverse NLRs converge on resistosome formation that ultimately drives Ca²⁺ influx as a central hub of defense activation. This paradigm shift underscores the functional conservation of NLR-mediated immunity across plant species and has fundamentally reshaped the field of plant innate immunity.