The Ubiquitin Proteasome and Abscisic Acid Signaling in Arabidopsis thaliana

Plants are sessile organisms that rely on the regulation of internal processes to deal with the stresses of their environment. Hormones are one regulator: plants synthesize hormone absisic acid (ABA) under drought stress to trigger stomatal closure, to reduce transpiration. Another regulator is the Ubiquitin Proteasome System (UPS) which degrades proteins tagged with Ubiquitin (Ub). Proteins degraded by the UPS are involved in processes such as stress response, and proper degradation is important for these processes’ proper function. F-Box proteins govern the substrate-specificity of Ub tagging in the UPS, with a different F-Box protein for different substrates. This study uses a genomics approach by analyzing publicly-sourced microarray data describing the transcriptome of Arabidopsis thaliana under dehydration stress and exogenous ABA treatments. The role of the UPS in drought-mediated ABA pathway is characterized by comparing the expression of F-Box genes to the expression of ABA pathway-involved marker genes NCED3 and rab18. This analysis yielded a list of 8 F-box genes with a potential role in the ABA synthesis/response pathway.