Figure 8
Overview of modulation of expression of genes involved in PGPR Dietzia natronolimnaea STR1-mediated salinity tolerance in wheat plants.
In the early steps of interaction, Dietzia natronolimnaea STR1 triggered signal transduction which modulated the expression of several genes responsible for salt tolerance. Based on the results we propose that carotenoid producing D. natronolimnaea STR1 participates in salt tolerance via both ABA-mediated and SOS-mediated pathways by up-regulating the expression of ABA-signalling cascade genes (TaABARE and TaOPR1), leading to induction of TaMYB and TaWRKY expression followed by stimulation of expression of a plethora of stress related genes including TaST, a salt stress-induced gene, associated with promoting salinity tolerance. Modulation of SOS pathway related genes (SOS1 and SOS4) and tissue specific responses of ion transporters TaNHX1, TaHAK and TaHKT1, were observed in PGPR applied plants. The enhanced gene expression of various antioxidant enzymes such as APX, MnSOD, CAT, POD, GPX and GR and higher proline content in PGPR-treated wheat plants contributed to increased plant tolerance to salinity stress. The red coloured bold arrows indicate the up-regulation or down-regulation of genes.
