Molecular cloning and characterization of salt inducible dehydrin gene from the C4 plant Pennisetum glaucum

Abstract

Dehydrins (DHNs) or group 2 LEA (late embryogenesis abundant) proteins play a protective role in plants under different abiotic stress conditions like drought, salinity, cold and heat stress. DHNs are expressed in late embryogenesis and accumulate in vegetative tissues in response to desiccation stress in all photosynthetic organisms. Here we report the cloning and characterization of a PgDHN gene from the C4 plant Pennisetum glaucum. The PgDHN cDNA encoded for a polypeptide of 133 amino acids with an estimated molecular weight of 13.87kDa and isoelectric point of 6.81. The protein sequence analysis of PgDHN classified it into the YnSKn subgroup of dehydrins. Phylogenetic analysis revealed that PgDHN is evolutionarily related to a Setaria italica DHN. In silico sequence analysis of the PgDHN promoter identified a distinct set of cis-elements and transcription factor binding sites. PgDHN mRNA accumulated in leaves of P. glaucum upon treatment with NaCl stress. Recombinant PgDHN transformed E. coli cells showed improved tolerance and exhibited better growth rate under high salt concentration (750mM) and heat stress in comparison to their respective controls. Heterologous expression of PgDHN in transgenic yeast showed increased tolerance to multiple abiotic stresses. This study provides a possible role of PgDHN in stress adaptation and stress tolerance in pearl millet.