, a Small Family of ABA Up-Regulated EAR Motif-Containing Proteins Regulate ABA Responses in Arabidopsis.

The abscisic acid (ABA) signaling pathway is crucial for regulating downstream ABA-responsive genes, which influence plant responses to ABA and abiotic stresses. However, many ABA-responsive genes remain poorly characterized. This study reports on the identification and characterization of ABA up-regulated EAR motif-containing proteins (), a novel family of EAR motif-containing proteins in . From a previous transcriptome dataset, were identified as a family of unknown-function ABA-response genes with only five members, and the up-regulation of by ABA was further confirmed by quantitative RT-PCR (qRT PCR). All contain at least one LxLxL EAR motif and can repress reporter gene expression in Arabidopsis protoplasts. We generated CRISPR/Cas9 gene-edited , and single, () double, and () triple mutants, as well as transgenic plants overexpressing , and examined their ABA sensitivity. We found that the single and double mutants displayed wild-type responses to ABA treatment, while the triple mutants showed increased sensitivity in seed germination and cotyledon greening assays but decreased sensitivity to ABA treatment in root elongation assays. Conversely, the showed decreased sensitivity in seed germination and cotyledon greening assays but increased sensitivity to ABA treatment in root elongation assays. The qRT PCR results show that the expression level of was increased in the mutants and decreased in the plants. These findings suggest that function redundantly to regulate ABA responses in Arabidopsis, likely by modulating the expression of key regulatory genes in ABA-signaling pathway.