RT Journal Article SR Electronic T1 The Cf-4 receptor-like protein associates with the BAK1 receptor-like kinase to initiate receptor endocytosis and plant immunity JF bioRxiv FD Cold Spring Harbor Laboratory SP 019471 DO 10.1101/019471 A1 Jelle Postma A1 Thomas W. H. Liebrand A1 Guozhi Bi A1 Alexandre Evrard A1 Ruby R. Bye A1 Malick Mbengue A1 Matthieu H. A. J. Joosten A1 Silke Robatzek YR 2015 UL http://biorxiv.org/content/early/2015/05/20/019471.abstract AB The first layer of plant immunity is activated by cell surface receptor-like kinases (RLKs) and proteins (RLPs) that detect infectious pathogens. Constitutive interaction with the RLK SUPPRESSOR OF BIR1 (SOBIR1) contributes to RLP stability and kinase activity. As RLK activation requires transphosphorylation with a second associated RLK, it remains elusive how RLPs initiate downstream signaling. To address this, we investigated functioning of Cf RLPs that mediate immunity of tomato against Cladosporium fulvum.We employed live-cell imaging and co-immunoprecipitation in tomato and Nicotiana benthamiana to investigate the requirement of associated kinases for Cf activity and ligand-induced subcellular trafficking of Cf-4.Upon elicitation with the matching effector ligands Avr4 and Avr9, BRI1-ASSOCIATED KINASE 1 (BAK1) associates with Cf-4 and Cf-9. Furthermore, Cf-4 that interacts with SOBIR1 at the plasma membrane, is recruited to late endosomes after elicitation. Significantly, BAK1 is required for Avr4-triggered endocytosis, effector-triggered defenses in Cf-4 plants and resistance of tomato against C. fulvum.Our observations indicate that RLP-mediated immune signaling and endocytosis require ligand-induced recruitment of BAK1, reminiscent of BAK1 interaction and subcellular fate of the FLAGELLIN SENSING 2 RLK. This reveals that diverse classes of cell surface immune receptors share common requirements for signaling initiation and endocytosis.