Coordination of auxin and ethylene biosynthesis by the aminotransferase VAS1

We identify an Arabidopsis pyridoxal-phosphate (PLP)-dependent aminotransferase, VAS1, whose loss-of-function simultaneously increases levels of the phytohormone auxin and the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC). VAS1 uses the ethylene biosynthetic intermediate Met as an amino donor and the auxin biosynthetic intermediate, indole-3-pyruvic acid (3-IPA) as an amino acceptor to produce L-Trp and 2-oxo-4-methylthiobutyric acid (KMBA). Our data indicate that VAS1 serves key roles in coordinating the levels of these two vital hormones.