Quantification of salinity-induced gene expression in young AGB1-deficient roots

To further investigate the gene expression profiles in agb1 mutant seedlings responding to salt stress, we employed whole transcriptome microarray expression profiling as a discovery platform to identify genes with the potential to be regulated by AGB1-mediated signaling cascades. Arabidopsis thaliana 7-day-old wild-type and agb1-3 mutant roots were challenged by immersing in 150 mM NaCl containing MS liquid media for 0 or 4 hours, and 4,830 genes induced by high salinity were identified that distinguished between zero and four hours among wild-type and agb1-3 samples. Thirteen of the 22 gene expressions that are transcriptionally regulated by bZIP17 under salt stress were decreased in agb1-3 compared to wild-type roots. The expression of three genes (NAC019, RD20, and TSPO) from this group was quantified in the same RNA samples by real-time PCR, confirming lower expression in both agb1-3 and bzip17-4 roots. Salinity induced gene expression in 7-day-old Arabidopsis thaliana wild-type (Col-0 ecotype) and agb1-3 mutant root was treated with 150 mM NaCl for 0 and 4 hours in MS lipid media. Three independent experiments were performed at each time (0 or 4 hours).