ETHYLENE RESPONSE FACTOR 74 (ERF74) plays an essential role in controlling a respiratory burst oxidase homolog D (RbohD)-dependent mechanism in response to different stresses in Arabidopsis.

Recent studies indicate that the ETHYLENE RESPONSE FACTOR VII (ERF-VII) transcription factor is an important regulator of osmotic and hypoxic stress responses in plants. However, the molecular mechanism of ERF-VII-mediated transcriptional regulation remains unclear. Here, we investigated the role of ERF74 (a member of the ERF-VII protein family) by examining the abiotic stress tolerance of an ERF74 overexpression line and a T-DNA insertion mutant using flow cytometry, transactivation and electrophoretic mobility shift assays. 35S::ERF74 showed enhanced tolerance to drought, high light, heat and aluminum stresses, whereas the T-DNA insertion mutant erf74 and the erf74;erf75 double mutant displayed higher sensitivity. Using flow cytometry analysis, we found that erf74 and erf74;erf75 lines lack the reactive oxygen species burst in the early stages of various stresses, as a result of the lower expression level of RESPIRATORY BURST OXIDASE HOMOLOG D (RbohD). Furthermore, ERF74 directly binds to the promoter of RbohD and activates its expression under different abiotic stresses. Moreover, induction of stress marker genes and enzyme genes under various stress conditions is dependent on the signal pathway. We propose a pathway that involves ERF74 acting as an on-off switch controlling an RbohD-dependent mechanism in response to different stresses, subsequently maintaining hydrogen peroxide (H₂ O₂ ) homeostasis in Arabidopsis.

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