Identification of AtGBF3-regulated targets in Arabidopsis thaliana under combined stress of drought and Pseudomonas syringae infection

Crop plants are often exposed to the combination of drought and pathogen stress. Transcriptome studies on Arabidopsis thaliana and other plants unveiled activation of shared molecular defense mechanisms between under individual and combined stresses. These shared plant responses are characterized by commonly regulated genes under individual and combined stresses. Based on the previous studies, G-box binding factor 3 (GBF3) is one of the regulatory components of such shared responses. However, the mechanistic understanding on the role of GBF3 under combined drought and pathogen stress is not yet decoded. Using genetic approaches, we demonstrated Atgbf3 mutant plants are more susceptible under individual and combined drought and Pseudomonas syringae pv. tomato DC3000 stresses as compared to the wild-type plants. We further analyzed the global transcriptome of Atgbf3 mutant under combined stress to identify its downstream targets to further validate the role of AtGBF3 in combined stress. We used microarrays to detail the global transcriptome reprogramming during AtGBF3-mediated regulation of combined stress. Leaves of mock treated and combined drought and P. syringae stressed Col-0 and Atgbf3 mutant plants for RNA extraction and hybridization on Affymetrix microarrays.