The transcriptional regulation of Arabidopsis ECT8 by ABA-Responsive Element binding transcription factors in response to ABA and abiotic stresses.

Abstract

N ⁶-methyladenosine modification is a critical epigenetic mark in the plant response to abscisic acid (ABA) and various abiotic stresses including salinity, drought, and cold stresses. Arabidopsis Evolutionarily Conserved C-Terminal Region 8 (ECT8), an m⁶A reader, has been reported to participate in the response to ABA and salinity stress. However, the intricate regulatory mechanisms governing ECT8 expression in these stress responses have not been fully elucidated. Our multidisciplinary analyses have revealed that ECT8 exhibits a broad expression pattern across tissues, with particularly high levels observed in senescent leaves. Furthermore, ECT8 expression is markedly upregulated in response to ABA, salinity, and osmotic stress. Intriguingly, the promoter region of the ECT8 gene harbors two ABA Responsive Elements (ABREs). Employing yeast one-hybrid assays, we identified that key ABRE-binding transcription factors within the ABA signaling cascade, namely ABA INSENSITIVE 5 (ABI5) and ABRE BINDING FACTOR1/2/3/4 (ABF1/2/3/4), exhibit a specific binding affinity for the ECT8 promoter, with the two ABREs indispensable for their interaction. The Dual-Luciferase Reporter assay and Chromatin immunoprecipitation assay confirmed their interaction in planta. The expression pattern of ECT8 in mutants deficient in the core components of the ABA signaling pathway indicated that ECT8 is modulated by ABI5/ABF-mediated ABA signaling. Collectively, our findings elucidate the feedback mechanism linking ABA perception to the regulation of ECT8 expression, thereby shedding new light on the intricate interplay between ABA signaling and RNA m⁶A modification. This discovery enriches our understanding of the molecular crosstalk that underpins plant stress responses.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-025-01565-7.