S-nitrosylation of the zinc finger protein SRG1 regulates plant immunity

Abstract

Nitric oxide (NO) orchestrates a plethora of incongruent plant immune responses, including the reprograming of global gene expression. However, the cognate molecular mechanisms remain largely unknown. Here we show a zinc finger transcription factor (ZF-TF), SRG1, is a central target of NO bioactivity during plant immunity, where it functions as a positive regulator. NO accumulation promotes SRG1 expression and subsequently SRG1 occupies a repeated canonical sequence within target promoters. An EAR domain enables SRG1 to recruit the corepressor TOPLESS, suppressing target gene expression. Sustained NO synthesis drives SRG1 S-nitrosylation predominantly at Cys87, relieving both SRG1 DNA binding and transcriptional repression activity. Accordingly, mutation of Cys87 compromises NO-mediated control of SRG1-dependent transcriptional suppression. Thus, the SRG1-SNO formation may contribute to a negative feedback loop that attenuates the plant immune response. SRG1 Cys87 is evolutionary conserved and thus may be a target for redox regulation of ZF-TF function across phylogenetic kingdoms.

Glutathione‐dependent denitrosation of GSNOR1 promotes oxidative signalling downstream of H2O2

“…Redox effects of NO are thought to be mainly linked to protein S ‐nitrosation, an oxidative modification in which NO is covalently attached to a reactive protein cysteine (Cys) to form an S ‐nitrosothiol (SNO; Gupta et al, ). This process has been shown to alter protein conformation, DNA‐protein interactions, protein stability, and enzyme activities in plants and other eukaryotic organisms (Cui et al, ; Frungillo, Skelly, Loake, Spoel, & Salgado, ; Lindermayr, Sell, Müller, Leister, & Durner, ; Stomberski, Hess, & Stamler, ; Tada et al, ; Wang et al, ; Yun et al, ; Zhan et al, ). For example, S ‐nitrosation of nonexpressor of pathogenesis‐related genes 1 (NPR1) regulates SA‐related responses by promoting formation of NPR1 oligomers and favouring retention of the protein in the cytosol (Tada et al, ).…”

Comparative Genomics of Six Juglans Species Reveals Patterns of Disease-associated Gene Family Contractions

“…The contraction of an SRG1 annotated gene family in J. hindsii could be related to phenology differences. The abscisic acid (ABA) and ethylene induced (Sui et al 2015) zinc-finger transcription factor, SRG1 has been implicated in leaf senescence in Arabidopsis (Callard et al 1996, Cui et al 2018) and fruit ripening in strawberry (Chen et al 2016). Discovering additional contractions (and expansions) in phenology-related gene families between closely related species might set a natural experiment for establishing the genetic signatures correlated with species susceptible to climate change-associated fitness loss.…”

Defluorosilylation of Industrially Relevant Fluoroolefins Using Nucleophilic Silicon Reagents

“…[5][6][7] In contrast, s-block silyl anions (M-SiR 3 ;M= Li, Na, K) have been invoked as intermediates in highly efficient methods for the defluorosi-lylation of sp 2 C À Fbonds of fluoroarenes and terminal sp 3 C À Fb onds of fluoroalkanes. [8][9][10][11] In related studies we,a nd others,h ave shown that main group nucleophiles are exceptional reagents for the CÀFfunctionalisation of fluoroarenes, fluoroalkenes and fluoroalkanes. [12][13][14][15][16][17] Strong M-F interactions provide al arge thermodynamic driving force for the reaction and can also play arole in determining the selectivity of which C À Fbond reacts.…”

“…2a reacts with hexafluoropropene or trifluoropropene but only at high temperature (100 8 8C) over long reaction periods. 2b did not react with hexafluoropropene despite heating for several days at (12),N ÀMgÀN90.04 (10). 2b:M g ÀN2.0040(15) and 2.0615 (16), MgÀ Si 2.6022(9), NÀMgÀN9 1.28 (6).…”