A novel lectin receptor kinase gene, AtG-LecRK-I.2, enhances bacterial pathogen resistance through regulation of stomatal immunity in Arabidopsis

• Published in: Plant science (Limerick) 2024-06, Vol.343, p.112071-112071, Article 112071
• Main Authors: Chien, Chih-Cheng, Chang, Chuan-Hsin, Ting, Hieng-Ming
• Format: Article
• Language: English
• Subjects: AHA1; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; BAK1; Flg22; FLS2; G-LecRK-I.2; Gene Expression Regulation, Plant; Plant Diseases - microbiology; Proton-Translocating ATPases - genetics; Pseudomonas syringae - physiology; Pst DC3000; Reactive Oxygen Species - metabolism; Receptors, Mitogen - genetics; Stomatal immunity
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2024.112071

The S-locus lectin receptor kinases (G-LecRKs) have been suggested as receptors for microbe/damage-associated molecular patterns (MAMPs/DAMPs) and to be involved in the pathogen defense responses, but the functions of most G-LecRKs in biotic stress response have not been characterized. Here, we identified a member of this family, G-LecRK-I.2, that positively regulates flg22- and Pseudomonas syringae pv. tomato (Pst) DC3000-induced stomatal closure. G-LecRK-I.2 was rapidly phosphorylated under flg22 treatment and could interact with the FLS2/BAK1 complex. Two T-DNA insertion lines, glecrk-i.2–1 and glecrk-i.2–2, had lower levels of reactive oxygen species (ROS) and nitric oxide (NO) production in guard cells, as compared with the wild-type Col-0, under Pst DC3000 infection. Also, the immunity marker genes CBP60g and PR1 were induced at lower levels under Pst DC3000 hrcC- infection in glecrk-i.2–1 and glecrk-i.2–2. The GUS reporter system also revealed that G-LecRK-I.2 was expressed only in guard cells. We also found that G-LecRK-I.2 could interact H+-ATPase AHA1 to regulate H+-ATPase activity in the guard cells. Taken together, our results show that G-LecRK-I.2 plays an important role in regulating stomatal closure under flg22 and Pst DC3000 treatments and in ROS and NO signaling specifically in guard cells. •We identified a novel receptor, G-LecRK-I.2, involved in stomatal immunity.•G-LecRK-I.2 was expressed and mediated defense signaling in the guard cells.•glecrk-i.2 mutants had lower levels of ROS in guard cells compared to Col-0.•G-LecRK-I.2 was required for full immunity under Pst DC3000 and flg22 treatments.•G-LecRK-I.2 could interact with the FLS2/BAK1 complex and AHA1.