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 'Sa beta NAC' encoding the p subunit of nascent polypeptide associated complex from a halophyte Spartina alterniflora and investigated its role toward abiotic stress regulation. Expression of Sa beta NAC was differentially regulated by abiotic stresses, including salinity, drought, cold, and ABA in leaves and roots of S. alterniflora. Constitutive over-expression of Sa beta NAC in Arabidopsis exhibited normal growth under non-stress conditions but enhanced tolerance to salt and drought stresses. Transgenic Sa beta NAC 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 beta NAC 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. (c) 2012 Elsevier Inc. All rights reserved.