Ectopic expression of AmNAC1 from Avicennia marina (Forsk.) Vierh. confers multiple abiotic stress tolerance in yeast and tobacco

Abiotic factors like salinity, drought and cold affect agricultural productivity substantially worldwide. NAC (NAM, ATAF1/2 and CUC2) family transcription factors have been shown to play important roles in biotic and abiotic stress responses in many plant species. Our previous studies have shown that AmNAC1, a gene from mangrove Avicennia marina, is differentially regulated in response to salt, drought and cold stresses and salicylic acid treatment. To gain more insights into the function of AmNAC1 in abiotic stress, AmNAC1 was heterologously expressed in yeast and tobacco. Heterologous expression of AmNAC1 in yeast (Saccharomyces cerevisiae) resulted in improved tolerance to salinity (NaCl and LiCl), alkalinity (NaHCO3) stresses. In addition, transgenic yeast exhibited enhanced tolerance compared to control when subjected to high (50 degrees C) and freezing (- 20 degrees C) temperature. Similarly, overexpression of AmNAC1 in tobacco using the constitutive promoter (2xCaMV) demonstrated increased tolerance to abiotic stresses such as salinity, drought and cold. Specifically, compared to wild type (WT) and vector control (VC), AmNAC1 transgenic lines exhibited higher germination, increased root length and better survival rates at the whole plant level. Collectively, these results indicate a role for AmNAC1 in multiple abiotic stress tolerance. Key message AmNAC1 is a stress responsive transcription factor from mangrove Avicennia marina and enhances better tolerance to NaCl, NaHCo3, LiCl, freezing and high temperature in transgenic yeast. Over expression of AmNAC1 in tobacco improved salt, cold and drought tolerance.