Arabidopsis thaliana NGATHA1 transcription factor induces ABA biosynthesis by activating NCED3 gene during dehydration stress

Significance The plant hormone abscisic acid (ABA) is essential for drought-stress responses in plants, and its functions have been well studied; however, the detailed molecular mechanisms of ABA biosynthesis during early drought stress need to be further explored. The present study identified a transcription factor, NGTHA1 (NGA1), which positively regulates ABA accumulation during dehydration stress by activating the NCED3 gene encoding a key ABA biosynthetic enzyme. We also identified a cis -acting element bound by NGA1 in the 5′ untranslated region (5′ UTR) of the NCED3 promoter. The NGA1 protein was degraded under nonstressed conditions, but it was stabilized during dehydration stress in an ABA-independent pathway.