1. TIR domains of plant immune receptors are 2',3'-cAMP/cGMP synthetases mediating cell death.
- Author
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Yu D, Song W, Tan EYJ, Liu L, Cao Y, Jirschitzka J, Li E, Logemann E, Xu C, Huang S, Jia A, Chang X, Han Z, Wu B, Schulze-Lefert P, and Chai J
- Subjects
- Cell Death genetics, Cyclic AMP biosynthesis, Cyclic GMP biosynthesis, Ligases metabolism, NAD+ Nucleosidase metabolism, Plant Diseases, Plant Immunity physiology, Plant Proteins metabolism, Receptors, Immunologic metabolism, Receptors, Interleukin-1 metabolism, Nicotiana genetics, Nicotiana metabolism, Arabidopsis genetics, Arabidopsis Proteins metabolism
- Abstract
2',3'-cAMP is a positional isomer of the well-established second messenger 3',5'-cAMP, but little is known about the biology of this noncanonical cyclic nucleotide monophosphate (cNMP). Toll/interleukin-1 receptor (TIR) domains of nucleotide-binding leucine-rich repeat (NLR) immune receptors have the NADase function necessary but insufficient to activate plant immune responses. Here, we show that plant TIR proteins, besides being NADases, act as 2',3'-cAMP/cGMP synthetases by hydrolyzing RNA/DNA. Structural data show that a TIR domain adopts distinct oligomers with mutually exclusive NADase and synthetase activity. Mutations specifically disrupting the synthetase activity abrogate TIR-mediated cell death in Nicotiana benthamiana (Nb), supporting an important role for these cNMPs in TIR signaling. Furthermore, the Arabidopsis negative regulator of TIR-NLR signaling, NUDT7, displays 2',3'-cAMP/cGMP but not 3',5'-cAMP/cGMP phosphodiesterase activity and suppresses cell death activity of TIRs in Nb. Our study identifies a family of 2',3'-cAMP/cGMP synthetases and establishes a critical role for them in plant immune responses., (Copyright © 2022 Elsevier Inc. All rights reserved.)
- Published
- 2022
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