OsNAC15 regulates drought and salt tolerance in rice

The NAC (NAM, ATAF1/2 and CUC2) transcription factors (TFs) play important roles in rice abiotic stress tolerance. OsNAC15 has been reported to regulate zinc deficiency and cadmium tolerance. However, the roles of OsNAC15 in rice drought and salt tolerance are largely unknown. In this study, we characterized a nuclear-localized NAC TF in rice, OsNAC15, that positively regulates drought and salt tolerance and directly participates in the biosynthesis of abscisic acid (ABA). Drought and salt treatment significantly induce the expression of OsNAC15. Loss of OsNAC15 could made plants more sensitive to drought and salt stress and led to the accumulation of more H2O2 and malondialdehyde (MDA) in vivo after drought and salt stress, while overexpression of OsNAC15 in plants showed stronger tolerance to drought and salt stress. Results of yeast one-hybrid assay and dual-luciferase (LUC) assay revealed that OsNAC15 interacted with the promoters of nine-cis-epoxycarotenoid dehydrogenases (NCEDs) genes (OsNCED1, OsNCED2 and OsNCED5), which are essential genes for ABA biosynthesis in rice, and promoted the expression of these target genes. In summary, our study reveals that OsNAC15, a NAC TF, may enhance drought and salt tolerance in rice by activating the promoters of key ABA biosynthesis genes (OsNCED1, OsNCED2 and OsNCED5). These results can contribute to further study on the regulatory mechanisms of drought and salt tolerance in rice.