Swammerdam Institute for Life Sciences

Research line dr. ir. H.A. (Harrold) van den Burg

SUMO-mediated transcriptional regulation of defense responses

A critical aspect of a successful defense response is the ability of a plant to rapidly mount a defense response upon pathogen attack. This defense response heavily relies on transcriptional reprogramming in the first hours after invasion, and often results in programmed cell death and the accumulation of anti-microbial compounds. Combined, these responses provide resistance to a broad range of invaders. In non-infected plants the defense response is suppressed. Our research indicated that the protein SUMO (small ubiquitin-like modifier) acts as a transcriptional repressor for the first wave of defense genes, but it allows a rapid induction upon recognition of an invading pathogen

SUMO acts as a protein modification, which means that is covalently coupled to other proteins. In the case of SUMO these targets are predominantly nuclear proteins. Conjugation of SUMO to transcription factors is known to induce changes in the activity and composition of transcription complexes via recruitment of chromatin-modifying enzymes. Chromatin-modifying enzymes determine the accessibility of the DNA for transcription by compacting and/or decorating DNA and histone proteins that together constitute chromatin. These decorations are considered to be the second genetic code

Currently, little is know about the role chromatin remodeling has on the regulation of the plant defense response. Our research on the model system Arabidopsis thaliana (thale crest) indicates that SUMO acts as a ‘hand-break’ of the plant defense system. Currently we are studying how SUMO affects the chromatin structure of defense genes and how this affects their expression

10 December 2012