A dehydration‐induced NAC protein, RD26, is involved in a novel ABA‐dependent stress‐signaling pathway

TLDR

RD26 is a NAC transcription factor isolated from dehydrated Arabidopsis thaliana plants. RD26 is a nuclear NAC transcription factor whose expression is induced by drought, ABA, and salinity; overexpression heightens ABA sensitivity and upregulates ABA‑ and stress‑responsive genes, while repression reduces sensitivity and downregulates these genes, demonstrating that RD26 acts as a transcriptional activator in ABA‑dependent stress signaling.

Abstract

Summary Arabidopsis thaliana RD26 cDNA, isolated from dehydrated plants, encodes a NAC protein. Expression of the RD26 gene was induced not only by drought but also by abscisic acid (ABA) and high salinity. The RD26 protein is localized in the nucleus and its C terminal has transcriptional activity. Transgenic plants overexpressing RD26 were highly sensitive to ABA, while RD26 ‐repressed plants were insensitive. The results of microarray analysis showed that ABA‐ and stress‐inducible genes are upregulated in the RD26 ‐overexpressed plants and repressed in the RD26 ‐repressed plants. Furthermore, RD26 activated a promoter of its target gene in Arabidopsis protoplasts. These results indicate that RD26 functions as a transcriptional activator in ABA‐inducible gene expression under abiotic stress in plants.