A lectin receptor-like kinase mediates pattern-triggered salicylic acid signaling

Abstract

Plant surface-localized pathogen recognition receptors (PRRs) perceive conserved microbial features, termed pathogen-associated molecular patterns (PAMPs), resulting in disease resistance. PAMP perception leads to calcium influx, MAPK activation, a burst of reactive oxygen species (ROS) mediated by RbohD, accumulation of the defense hormone salicylic acid (SA), and callose deposition. Lectin receptor-like kinases (LecRKs) belong to a specific PRR family and are important players in plant innate immunity. Here, we report that LecRK-IX.2 is a positive regulator of PRR-triggered immunity. Pathogen infection activated the transcription of Arabidopsis (Arabidopsis thaliana) LecRK-IX.2, and the LecRK-IX.2 knockout lines exhibited enhanced susceptibility to virulent Pseudomonas syringae pv tomato DC3000. In addition, LecRK-IX.2 is capable of inducing RbohD phosphorylation, likely by recruiting calcium-dependent protein kinases to trigger ROS production in Arabidopsis. Overexpression of LecRK-IX.2 resulted in elevated ROS and SAand enhanced systemic acquired resistance to P. syringae pv tomato DC3000. Our data highlight the importance of LecRKs in plant immune signaling and SA accumulation.