Arabidopsis NADPH oxidases, AtrbohD and AtrbohF, are essential for jasmonic acid-induced expression of genes regulated by MYC2 transcription factor

To clarify genetically the involvement of two Arabidopsis NADPH oxidases (AtrbohD and AtrbohF) in the jasmonic acid (JA) signaling pathway, we characterized single knockout mutants lacking either Atrboh. The accumulation of reactive oxygen species (ROS) and expression of the genes regulated by MYC2, a transcription factor involved in the JA-evoked response, were significantly suppressed by treatment with methyl JA (MeJA) in both mutants. Further experiments using knockout mutants lacking CORONATINE-INSENSITIVE1 (COI1), a master regulator of the JA-evoked response, and MYC2 indicated a possibility that the production of ROS via Atrbohs depends on the function of COI1, but not MYC2.

Research highlights
► We obtained and characterized knockout mutants lacking AtrbohD and AtrbohF (KO-rbohD and KO-rbohF, respectively), NADPH oxidases in Arabidopsis plants.
► The levels of H2O2 were increased by treatment with methyl jasmonate (MeJA) in the wild-type plants, but not in the KO-rbohD and KO-rbohF plants.
► The induction of ANAC019, ANAC055, and VSP1 expression by MeJA was observed in the wild-type plants, but not in the KO-rbohD and KO-rbohF plants.
► In the knockout mutants lacking CORONATINE-INSENSITIVE1, a master regulator of the JA-evoked response, the increase in H2O2 levels during treatment with MeJA was completely inhibited.