Isolation and characterization of stress inducible promoters from Pennisetum glaucum and their role in abiotic stress adaptation

Abiotic stresses including drought, salinity, oxidative stress, extreme temperatures and a combination of these stresses cause immense loss to agricultural crop production. These losses could be immensely reduced if the crops were able to tolerate these above mentioned conditions. This can be overcome by developing transgenic plants with stress inducible promoters with specific genes. Stress-inducible promoters have previously been identified, but there is a shortage of efficient promoters for gene expression that display favorable characteristics in their native plants as well as in xenogeneic species. In the present study five stress inducible promoters PgApx, PgDhn and PgHsc70, PgLea, PgHsp10 were isolated and functionally validated in the tobacco plants. Five stress inducible promoters were isolated using genome-walking method. Further, all five promoters were subjected to cis-motif analysis and identified several stress inducible and tissue specific cis-acting elements. These five full-length promoters were fused with uidA gene in plant transformation vector pMDC164 and transferred to tobacco. Putative transgenic positive plants were confirmed by PCR and positive plants advanced for T1 and T2 generations. Homozygous T2 transgenic plants were analysed for their tolerance to these stresses. The PgApx pro, PgDhn pro, PgHsc70, PgLea, PgHsp10 pro offers advantages over constitutive promoters to produce genetically modified tolerant crops to these adverse conditions. In summary, PgHsc70 pro is active in high temperatures, PgDhn pro in heat, cold and drought and PgApx pro in drought stress, PgLea pro in heat and drought, PgHsp10 pro in control, heat, cold, salt and drought stress treatments.