The zinc-finger transcription factor ZFP8 negatively regulates the drought stress response in Arabidopsis thaliana by inhibiting the transcriptional activity of ABF2.

ABSTRACT

Drought stress limits plant growth and development. To cope with drought stress, abscisic acid (ABA) accumulates in plants. Although ABA-dependent drought tolerance pathways have been widely investigated, the feedback mechanisms and the negative regulatory roles within these pathways remain largely unknown. Here we characterize the roles of a C2H2 transcription factor, ZFP8, whose expression is repressed by ABA in the tolerance of drought stress. ZFP8-overexpressing plants were hyposensitive to ABA and exhibited less dehydration tolerance while ABA or drought-induced marker genes were more highly expressed in zfp8, suggesting that ZFP8 functions as a negative regulator in the ABA-mediated drought response. A transcriptome assay showed that ZFP8 positively regulates gene expression for cellular function and negatively regulates hormone and stress response gene expression. Moreover, we found that ZFP8 can interact with ABF2, one of the basic leucine zipper (bZIP) family transcription factor members, to inhibit its transcription activity. In conclusion, our results demonstrate a novel negative regulation pathway of ZFP8, which contributes to plants' ability to fine-tune their drought responses.