TY - JOUR TI - Dynamic ubiquitination determines transcriptional activity of the plant immune coactivator NPR1 AU - Skelly, Michael J AU - Furniss, James J AU - Grey, Heather AU - Wong, Ka-Wing AU - Spoel, Steven H A2 - Zhou, Jian-Min A2 - Hardtke, Christian S VL - 8 PY - 2019 DA - 2019/10/07 SP - e47005 C1 - eLife 2019;8:e47005 DO - 10.7554/eLife.47005 UR - https://doi.org/10.7554/eLife.47005 AB - Activation of systemic acquired resistance in plants is associated with transcriptome reprogramming induced by the unstable coactivator NPR1. Immune-induced ubiquitination and proteasomal degradation of NPR1 are thought to facilitate continuous delivery of active NPR1 to target promoters, thereby maximising gene expression. Because of this potentially costly sacrificial process, we investigated if ubiquitination of NPR1 plays transcriptional roles prior to its proteasomal turnover. Here we show ubiquitination of NPR1 is a progressive event in which initial modification by a Cullin-RING E3 ligase promotes its chromatin association and expression of target genes. Only when polyubiquitination of NPR1 is enhanced by the E4 ligase, UBE4, it is targeted for proteasomal degradation. Conversely, ubiquitin ligase activities are opposed by UBP6/7, two proteasome-associated deubiquitinases that enhance NPR1 longevity. Thus, immune-induced transcriptome reprogramming requires sequential actions of E3 and E4 ligases balanced by opposing deubiquitinases that fine-tune activity of NPR1 without strict requirement for its sacrificial turnover. KW - NPR1 KW - salicylic acid KW - systemic acquired resistance KW - plant immunity KW - ubiquitin JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -