Arabidopsis cysteine-rich receptor like kinases and their roles in amplifying plant immune responses
K. YADETA (1), A. Creer (1), J. Franco (1), J. Rufian (2), G. Coaker (1) (1) Department of Plant Pathology, University of California Davis, U.S.A.; (2) Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” – Universidad de Málaga, Spain

Cysteine-rich receptor-like kinases (CRKs) belong to the RLK superfamily and possess extracellular cysteine-rich domains. CRKs comprise a large gene family in land plants and consist of 46 members in Arabidopsis thaliana. The majority of CRKs are transcriptionally upregulated during biotic and abiotic stresses. However, the biological functions of CRKs are largely unknown. Here, we investigated the role of CRK28 during plant immune responses. CRK28's transcription was inhibited at a resting state but was strongly induced upon pathogen perception. Arabidopsis lines with enhanced expression of CRK28 exhibited a higher burst of reactive oxygen species in response to bacterial flagellin and enhanced resistance to Pseudomonas syringae. Transient expression of a subset of CRKs, including CRK28, induced cell death in Nicotiana benthamiana. CRK28 co-immunoprecipitated with the common co-receptor BAK1 and was present in the FLS2/BAK1 immune complex upon flagellin perception. BAK1 is also required for CRK28-induced cell death in N. benthamiana. Using co-immunoprecipitation, CRK28 self-associated and association with the closely related CRK29 was enhanced upon flagellin perception. The extracellular cysteine residues predicted to form disulfide bonds were also required for cell death induction. We propose a model in which CRK28 associates with immune receptor complexes and heterodimerizes with closely related CRKs to amplify immune signaling upon pathogen perception.

Abstract Number: P17-640
Session Type: Poster