Overexpression of VIRE 2- INTERACTING PROTEIN 2 in Arabidopsis regulates genes involved in Agrobacterium -mediated plant transformation and abiotic stresses

Arabidopsis VIRE2-INTERACTING PROTEIN2 (VIP2) was previously described as a protein with a NOT domain, and Arabidopsis vip2 mutants are recalcitrant to Agrobacterium-mediated root transformation. Here we show that VIP2 is a transcription regulator and the C-terminal NOT2 domain of VIP2 interacts with VirE2. Interestingly, AtVIP2 overexpressor lines in Arabidopsis did not show an improvement in Agrobacterium-mediated stable root transformation, but the transcriptome analysis identified 1,634 differentially expressed genes compared to wild-type. These differentially expressed genes belonged to various functional categories such as membrane proteins, circadian rhythm, signaling, response to stimulus, regulation of plant hypersensitive response, sequence-specific DNA binding transcription factor activity and transcription regulatory region binding. In addition to regulating genes involved in Agrobacterium-mediated plant transformation, AtVIP2 overexpressor line showed differential expression of genes involved in abiotic stresses. The majority of the genes involved in abscisic acid (ABA) response pathway, containing the Abscisic Acid Responsive Element (ABRE) element within their promoters, were down-regulated in AtVIP2 overexpressor lines. Consistent with this observation, AtVIP2 overexpressor lines were more susceptible to ABA and other abiotic stresses. Based on the above findings, we hypothesize that VIP2 not only plays a role in Agrobacterium-mediated plant transformation but also acts as a general transcriptional regulator in plants.