Identification and receptor mechanism of TIR-catalyzed small molecules in plant immunity

huang, s.; Jia, A.; Song, W.; Hessler, G.; Meng, Y.; Sun, Y.; Xu, L.; Laessle, H.; Jirschitzka, J.; Ma, S.; Xiao, Y.; Yu, D.; Hou, J.; Liu, R.; Sun, H.; Liu, X.; Han, Z.; Chang, J.; Parker, J. E.; Chai, J.

doi:10.1101/2022.04.01.486681

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bioRxiv · 10.1101/2022.04.01.486681

Identification and receptor mechanism of TIR-catalyzed small molecules in plant immunity

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Abstract

Plant nucleotide-binding leucine-rich-repeat receptors (NLRs) with an N-terminal toll/interleukin-1 receptor (TIR) domain sense pathogen effectors to enable TIR-encoded NADase activity for immune signaling. TIR-NLR (TNL) signaling requires conserved helper NLRs NRG1 and ADR1 and the lipase-like protein EDS1 that functions as a heterodimer with each of its paralogs PAD4 and SAG101. We show that TIR-containing proteins catalyze production of 2-(5-phosphoribosyl)-5-adenosine mono-/di-phosphate (pRib-AMP/ADP) in vitro and in planta. Biochemical and structural data demonstrate that EDS1-PAD4 is a receptor complex for pRib-AMP/ADP. pRib-ADP binding triggers a conformational change in the PAD4 C-terminal domain to allosterically promote EDS1-PAD4 interaction with ADR1-L1 but not NRG1A. Our study identifies TIR-catalyzed pRib-AMP/ADP as a missing link in TIR signaling via EDS1-PAD4 and as likely second messengers for plant immunity.

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huang, s., Jia, A., Song, W., Hessler, G., Meng, Y., Sun, Y., Xu, L., Laessle, H., Jirschitzka, J., Ma, S., Xiao, Y., Yu, D., Hou, J., Liu, R., Sun, H., Liu, X., Han, Z., Chang, J., Parker, J. E., Chai, J.. 2022-04-01. Identification and receptor mechanism of TIR-catalyzed small molecules in plant immunity. https://doi.org/10.1101/2022.04.01.486681

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