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The Arabidopsis zinc finger proteins SRG2 and SRG3 are positive regulators of plant immunity and are differentially regulated by nitric oxide
Author(s) -
Cui Beimi,
Xu Shiwen,
Li Yuan,
Umbreen Saima,
Frederickson Debra,
Yuan Bo,
Jiang Jihong,
Liu Fengquan,
Pan Qiaona,
Loake Gary J.
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.16993
Subject(s) - arabidopsis , biology , zinc finger transcription factor , neofunctionalization , plant immunity , microbiology and biotechnology , arabidopsis thaliana , transcription factor , zinc finger , psychological repression , genetics , repressor , mutant , immune system , plant defense against herbivory , innate immune system , immunity , gene , gene expression , gene duplication
Summary Nitric oxide (NO) regulates the deployment of a phalanx of immune responses, chief among which is the activation of a constellation of defence‐related genes. However, the underlying molecular mechanisms remain largely unknown. The Arabidopsis thaliana zinc finger transcription factor (ZF‐TF), S ‐nitrosothiol (SNO) Regulated 1 (SRG1), is a central target of NO bioactivity during plant immunity. Here we characterize the remaining members of the SRG gene family. Both SRG2 and, especially, SRG3 were positive regulators of salicylic acid‐dependent plant immunity. Analysis of SRG single, double and triple mutants implied that SRG family members have additive functions in plant immunity and, surprisingly, are under reciprocal regulation. SRG2 and SRG3 localized to the nucleus and functioned as ethylene‐responsive element binding factor‐associated amphiphilic repression (EAR) domain‐dependent transcriptional repressors: NO abolished this activity for SRG3 but not for SRG2. Consistently, loss of GSNOR function, resulting in increased (S)NO concentrations, fully suppressed the disease resistance phenotype established from SRG3 but not SRG2 overexpression. Remarkably, SRG3 but not SRG2 was S ‐nitrosylated in vitro and in vivo . Our findings suggest that the SRG family has separable functions in plant immunity, and, surprisingly, these ZF‐TFs exhibit reciprocal regulation. It is remarkable that, through neofunctionalization, the SRG family has evolved to become differentially regulated by the key immune‐related redox cue, NO.