TY - JOUR TI - A non canonical subtilase attenuates the transcriptional activation of defence responses in Arabidopsis thaliana AU - Serrano, Irene AU - Buscaill, Pierre AU - Audran, Corinne AU - Pouzet, Cécile AU - Jauneau, Alain AU - Rivas, Susana A2 - Stacey, Gary VL - 5 PY - 2016 DA - 2016/09/29 SP - e19755 C1 - eLife 2016;5:e19755 DO - 10.7554/eLife.19755 UR - https://doi.org/10.7554/eLife.19755 AB - 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 transcription factor 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. KW - transcription factors KW - plant defence KW - alternative splicing KW - subtilase KW - hypersensitive response JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -