Abstract

Aims R 2 R 3 -type MYB transcription factors are associated with diverse developmental processes and responses to abiotic stresses. However, there is limited information regarding drought-responsive R 2 R 3 -MYB in a widespread subtropical tree species, Schima superba . Hence, the purpose of this study was to identify and functionally characterize the role of SsMYB113 in S. superba under drought stress. Results SsMYB113, a novel R 2 R 3 -MYB transcription factor that was targeted to the nucleus in Arabidopsis thaliana protoplasts, functioned as a transcriptional activator during in vitro and in vivo assays. SsMYB113 transcript was abundant in the leaves of six-month-old S. superba , and was significantly up-regulated by PEG-simulated drought stress and abscisic acid (ABA). Overexpression of SsMYB113 in A. thaliana seedlings led to enhanced tolerance to drought stress and facilitated flavonoid biosynthesis and ABA accumulation, including of corresponding biosynthetic genes, particularly SsCHS and SsNCED . Furthermore, SsMYB113 was shown to bind directly to the promoters of SsCHS and SsNCED using Y1H and a dual-LUC assay, thus activating their expression. In addition, in SsMYB113 -overexpressing lines, proline, water content, superoxide dismutase, and peroxidase activities increased, while malondialdehyde, electrolyte leakage, and the rate of superoxide production decreased, suggesting the explicit role of SsMYB113 in conferring drought tolerance. Conclusions Drought-responsive SsMYB113 functioned as a positive regulator by participating in flavonoid and ABA biosynthesis, thereby enhancing drought stress tolerance in indigenous fast-growing S. superba .