Transcriptome analysis of an Arabidopsis thaliana atark mutant.

In Arabidopsis, ABA signaling is transmitted through activation of a plant-specific kinase SnRK2. Previously we identified an ARK belonging to the group B3 MAPKKK as a novel upstream factor of SnRK2 in the moss Physcomitrella patens. ARK was essential for ABA- and osmostress-induced activation of SnRK2 in P. patens. Arabidopsis has 6 genes belonging to B3 MAPKKK and we showed that 3 genes (AtARK1, AtARK2, AtARK3) could complement ARK function in P. patens. To gain insight into the function of B3 MAPKKK in ABA and osmostress responses in Arabidopsis, we performed a transcriptome analysis of atark triple mutant and WT plants treated with 50 ?M ABA or osmostress (300 mM) sorbitol for 1h and 3h.