ABA 9′-hydroxylation is catalyzed by CYP707A in Arabidopsis

► The Arabidopsis mutant for ABA 8′-hydroxylase reduced accumulation of neoPA. ► NeoPA accumulation was inhibited by uniconazole-P, a P450 inhibitor. ► CYP707A contains both ABA 8′- and 9′-hydroxylase activity in vitro.