A non canonical subtilase attenuates the transcriptional activation of defence responses in Arabidopsis thaliana
Abstract
Proteases play crucial physiological functions in all organisms by controlling the lifetime of proteins. Here, we identified an atypical protease of the subtilase family [SBT5.2(b)] that attenuates the transcriptional activation of plant defence independently of its protease activity. The SBT5.2 gene produces two distinct transcripts encoding a canonical secreted subtilase [SBT5.2(a)] and an intracellular protein [SBT5.2(b)]. Concomitant to SBT5.2(a) downregulation, SBT5.2(b) expression is induced after bacterial inoculation. SBT5.2(b) localizes to endosomes where it interacts with and retains the defence-related TF MYB30. Nuclear exclusion of MYB30 results in its reduced transcriptional activation and, thus, suppressed resistance. sbt5.2 mutants, with abolished SBT5.2(a) and SBT5.2(b) expression, display enhanced defence that is suppressed in a myb30 mutant background. Moreover, overexpression of SBT5.2(b), but not SBT5.2(a), in sbt5.2 plants reverts the phenotypes displayed by sbt5.2 mutants. Overall, we uncover a regulatory mode of the transcriptional activation of defence responses previously undescribed in eukaryotes.
Article and author information
Author details
Funding
Institut National de la Recherche Agronomique and Agreenskills
- Irene Serrano
Freach Ministry of National Education and Research
- Pierre Buscaill
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Gary Stacey, University of Missouri, United States
Version history
- Received: July 17, 2016
- Accepted: September 28, 2016
- Accepted Manuscript published: September 29, 2016 (version 1)
- Version of Record published: October 21, 2016 (version 2)
Copyright
© 2016, Serrano et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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