The COP9 signalosome controls XXXX synthesis and plant responses to herbivory and pathogens.

@entity4079 @entity3785 @entity7214 @entity21104 @entity14261 @entity523
The COP9 signalosome (CSN) is a multi-protein complex that regulates the activities of cullin-RING E3 ubiquitin ligases (CRLs). CRLs ubiquitinate proteins in order to target them for proteasomal degradation. The CSN is required for proper plant development. Here we show that the CSN also has a profound effect on plant defense responses. Silencing of genes for CSN subunits in @entity523 plants resulted in a mild morphological phenotype and reduced expression of wound-responsive genes in response to mechanical wounding, attack by @entity4079 larvae, and Prosystemin over-expression. In contrast, expression of pathogenesis-related genes was increased in a stimulus-independent manner in these plants. The reduced wound response in CSN-silenced plants corresponded with reduced synthesis of @entity7214 (JA), but levels of @entity3785 (SA) were unaltered. As a consequence, these plants exhibited reduced resistance against herbivorous @entity4079 larvae and the necrotrophic fungal pathogen @entity14261 . In contrast, susceptibility to @entity21104 ) was not altered in CSN-silenced plants. These data demonstrate that the CSN orchestrates not only plant development but also JA-dependent plant defense responses.
