Overexpression of a nascent polypeptide associated complex gene (SaβNAC) of Spartina alterniflora improves tolerance to salinity and drought in transgenic Arabidopsis

Salinity and drought are the most important environmental constraints limiting crop growth and productivity. Here, we have characterized a gene ‘SaβNAC’ encoding the β subunit of nascent polypeptide associated complex from a halophyte Spartina alterniflora and investigated its role toward abiotic stress regulation. Expression of SaβNAC was differentially regulated by abiotic stresses, including salinity, drought, cold, and ABA in leaves and roots of S. alterniflora. Constitutive over-expression of SaβNAC in Arabidopsis exhibited normal growth under non-stress conditions but enhanced tolerance to salt and drought stresses. Transgenic SaβNAC Arabidopsis retained more chlorophyll, proline, and showed improved ionic homeostasis with less damage under stress conditions compared to WT plants. This is a first report to demonstrate the involvement of βNAC in imparting abiotic stress tolerance which might be due to protection of the newly synthesized polypeptides involved in various stress tolerance mechanisms from abiotic stress induced damage and inhibition of cell death in plant.

► We characterized SaβNAC gene from a grass halophyte Spartina alterniflora. ► Expression of SaβNAC was differentially regulated under different abiotic stresses. ► Transgenic Arabidopsis with SaβNAC enhanced both salt and drought tolerance. ► SaβNAC may be protecting the nascent proteins from abiotic stress induced damage. ► Genes from halophytes may improve abiotic stress tolerance in field crops.