SUMOylation: re-wiring the plant nucleus during stress and development

Conjugation of small ubiquitin-related modifier (SUMO) to intracellular proteins provides a dynamic regulatory mechanism that enables plants to rapidly defend against environmental challenges. SUMOylation of mostly nuclear proteins is among the fastest stress responses observed but precisely how this post-translational modification provides stress resilience remains unclear. Here, we describe the plant SUMO system and its expanding target catalog, which implicates this modification in DNA repair, chromatin modification/remodeling, transcriptional activation/repression, epigenetics, and RNA metabolism, with a likely outcome being extensive nuclear re-wiring to withstand stress. In parallel, studies have linked SUMO to developmental programs such as gametogenesis and gene silencing. The accumulating data support the notion that SUMOylation substantially influences the transcriptional and epigenetic landscapes to promote stress tolerance and developmental progression.