NbCSPR underlies age-dependent immune responses to bacterial cold shock protein in Nicotiana benthamiana.

Abstract

Plants use receptor kinases (RKs) and receptor-like proteins (RLPs) as pattern recognition receptors (PRRs) to sense pathogen-associated molecular patterns (PAMPs) that are typical of whole classes of microbes. After ligand perception, many leucine-rich repeat (LRR)-containing PRRs interact with the LRR-RK BRI1-ASSOCIATED KINASE 1 (BAK1). BAK1 is thus expected to interact with unknown PRRs. Here, we used BAK1 as molecular bait to identify a previously unknown LRR-RLP required for the recognition of the csp22 peptide derived from bacterial cold shock protein. We established a method to identify proteins that interact with BAK1 only after csp22 treatment. BAK1 was expressed transiently in Nicotiana benthamiana and immunopurified after treatment with csp22. BAK1-associated proteins were identified by mass spectrometry. We identified several proteins including known BAK1 interactors and a previously uncharacterized LRR-RLP that we termed RECEPTOR-LIKE PROTEIN REQUIRED FOR CSP22 RESPONSIVENESS (NbCSPR). This RLP associates with BAK1 upon csp22 treatment, and NbCSPR-silenced plants are impaired in csp22-induced defense responses. NbCSPR confers resistance to bacteria in an age-dependent and flagellin-induced manner. As such, it limits bacterial growth and Agrobacterium-mediated transformation of flowering N. benthamiana plants. Transgenic expression of NbCSPR into Arabidopsis thaliana conferred responsiveness to csp22 and antibacterial resistance. Our method may be used to identify LRR-type RKs and RLPs required for PAMP perception/responsiveness, even when the active purified PAMP has not been defined.

• Authors: Isabel M L Saur, Yasuhiro Kadota, Jan Sklenar, Nicholas J Holton, Elwira Smakowska, Youssef Belkhadir, Cyril Zipfel, John P Rathjen
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 113 Issue 12 Pg. 3389-94 (Mar 22 2016) ISSN: 1091-6490 [Electronic] United States
• PMID: 26944079 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• Cold Shock Proteins and Peptides

Topics

• Bacterial Proteins (immunology)
• Cold Shock Proteins and Peptides (physiology)
• Nicotiana (immunology, microbiology)