Soybean GmSAUL1, a Bona Fide U-Box E3 Ligase, Negatively Regulates Immunity Likely through Repressing the Activation of GmMPK3

Authors

Jun-Mei Li
Mei-Yan Ye
Chaofeng Wang
Xiao-Han Ma
Ni-Ni Wu
Chen-Li Zhong
Yanjun Zhang
Ninghui Cheng
Paul A Nakata
Lirong Zeng
Jian-Zhong Liu

Publication Date

3-25-2023

Journal

International Journal of Molecular Sciences

DOI

10.3390/ijms24076240

PMID

37047211

PMCID

PMC10094664

PubMedCentral® Posted Date

3-25-2023

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Ubiquitin-Protein Ligases, Glycine max, Phenotype, Plant Immunity, Gene Expression Regulation, Plant, Glycine max, E3 ligase, GmSAUL1, virus-induced gene silencing, immune responses, cell death, soybean

Abstract

E3 ubiquitin ligases play important roles in plant immunity, but their role in soybean has not been investigated previously. Here, we used Bean pod mottle virus (BPMV)-mediated virus-induced gene silencing (VIGS) to investigate the function of GmSAUL1 (Senescence-Associated E3 Ubiquitin Ligase 1) homologs in soybean. When two closely related SAUL1 homologs were silenced simultaneously, the soybean plants displayed autoimmune phenotypes, which were significantly alleviated by high temperature, suggesting that GmSAUL1a/1b might be guarded by an R protein. Interestingly, silencing GmSAUL1a/1b resulted in the decreased activation of GmMPK6, but increased activation of GmMPK3 in response to flg22, suggesting that the activation of GmMPK3 is most likely responsible for the activated immunity observed in the GmSAUL1a/1b-silenced plants. Furthermore, we provided evidence that GmSAUL1a is a bona fide E3 ligase. Collectively, our results indicated that GmSAUL1 plays a negative role in regulating cell death and immunity in soybean.