BRS1 mediates plant redox regulation and cold responses

Dongzhi Zhang,Yuqian Zhao,Shengbao Xu,Junzhe Wang,Peng Zhao

doi:10.1186/s12870-021-03045-y

Dongzhi Zhang, Yuqian Zhao + Show 3 more

Open Access

https://doi.org/10.1186/s12870-021-03045-y

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Abstract

BackgroundBrassinosteroid-insensitive 1 suppressor 1 (BRS1) is a serine carboxypeptidase that mediates brassinosteroid signaling and participates in multiple developmental processes in Arabidopsis. However, little is known about the precise role of BRS1 in this context.ResultsIn this study, we analyzed transcriptional and proteomic profiles of Arabidopsis seedlings overexpressing BRS1 and found that this gene was involved in both cold stress responses and redox regulation. Further proteomic evidence showed that BRS1 regulated cell redox by indirectly interacting with cytosolic NADP + -dependent isocitrate dehydrogenase (cICDH). One novel alternative splice form of BRS1 was identified in over-expression mutants brs1-1D, which may confer a new role in plant development and stress responses.ConclusionsThis study highlights the role of BRS1 in plant redox regulation and stress responses, which extends our understanding of extracellular serine carboxypeptidases.

Highlights

Brassinosteroid-insensitive 1 suppressor 1 (BRS1) is a serine carboxypeptidase that mediates brassinosteroid signaling and participates in multiple developmental processes in Arabidopsis
Analysis of the transcriptomes of BRS1 seedlings The RNA sequencing was performed on WS2, brs1-1 and brs1-1D seedlings, and showing the BRS1 in brs11 has an insertion of one thymidine at position 533 in the first intron (Fig. 2a) and a significant decrease in transcription (Fig. 2b)
The transcriptional level of BRS1 increased by around 20 times in the brs1-1D mutant (Fig. 2b), which is consistent with the presence of four copies of CaMV 35S enhancers inserted in the promoter region of BRS1 [5]

Summary

Introduction

Brassinosteroid-insensitive 1 suppressor 1 (BRS1) is a serine carboxypeptidase that mediates brassinosteroid signaling and participates in multiple developmental processes in Arabidopsis. Serine carboxypeptidases (SCP) are a class of eukaryotic proteolytic enzymes, belonging to the α/β hydrolase family. These enzymes contain a highly conserved catalytic amino acid triad, Ser-Asp-His [1]. In Arabidopsis, 54 SCP-like genes have been identified and categorized into three classes [2, 3]. Its over-expression can suppress the phenotype of brassinosteroid (BR) receptor mutant, bri, indicating BRS1 play an important role in BR signaling [4, 5]. No significant phenotypes have been identified in single or double mutants of either BRS1 or its homologs [5,6,7], indicating BRS1 and its homologs are functionally redundant in Arabidopsis

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