Maize nicotinate N‐methyltransferase interacts with the NLR protein Rp1‐D21 and modulates the hypersensitive response

• Published in: Molecular plant pathology 2021-05, Vol.22 (5), p.564-579
• Main Authors: Liu, Mengjie, Li, Ya‐Jie, Zhu, Yu‐Xiu, Sun, Yang, Wang, Guan‐Feng
• Format: Article
• Language: English
• Subjects: Apoptosis; Biosynthesis; Coils; Corn; Cytoplasm; Defense; Disease resistance; Enzymes; Evolution; Genes; Genotype & phenotype; Homology; Hypersensitive response; Infections; Leucine; Lignin; Localization; maize; Methyltransferase; Mutation; NANMT; Nlr protein; Nucleotides; Original; Pathogens; Phenotypes; Physiological aspects; Plant diseases; Plant immunity; plant innate immunity; Plant resistance; Plants; Proteins; Roles; Signal transduction; Transferases; Virulence (Microbiology)
• ISSN: 1464-6722; 1364-3703
• DOI: 10.1111/mpp.13044

Most plant intracellular immune receptors belong to nucleotide‐binding, leucine‐rich repeat (NLR) proteins. The recognition between NLRs and their corresponding pathogen effectors often triggers a hypersensitive response (HR) at the pathogen infection sites. The nicotinate N‐methyltransferase (NANMT) is responsible for the conversion of nicotinate to trigonelline in plants. However, the role of NANMT in plant defence response is unknown. In this study, we demonstrated that the maize ZmNANMT, but not its close homolog ZmCOMT, an enzyme in the lignin biosynthesis pathway, suppresses the HR mediated by the autoactive NLR protein Rp1‐D21 and its N‐terminal coiled‐coil signalling domain (CCD21). ZmNANMT, but not ZmCOMT, interacts with CCD21, and they form a complex with HCT1806 and CCoAOMT2, two key enzymes in lignin biosynthesis, which can also suppress the autoactive HR mediated by Rp1‐D21. ZmNANMT is mainly localized in the cytoplasm and nucleus, and either localization is important for suppressing the HR phenotype. These results lay the foundation for further elucidating the molecular mechanism of NANMTs in plant disease resistance. Maize ZmNANMT, but not its close homolog ZmCOMT, interacts with the NLR protein Rp1‐D21 and modulates the hypersensitive response when transiently expressed in Nicotiana benthamiana.