Impact of PGPR inoculation on growth and antioxidant status of wheat under saline conditions

Two plant growth-promoting rhizobacterial (PGPR) strains, Bacillus subtilis SU47 and Arthrobacter sp. SU18, were found to tolerate 8% NaCl. Wheat co-inoculated with these two PGPR strains, and grown under different salinity regimes (26 dS m-1), showed an increase in dry biomass, total soluble sugars and proline content. Wheat sodium content was reduced under co-inoculated conditions but not after single inoculation with either strain or in the control. The activity of antioxidant enzymes in wheat leaves decreased under salinity stress after PGPR co-inoculation, suggesting these PGPR species could be used for amelioration of stress in wheat plants. Activity of three antioxidant enzymes in wheat grown with both PGPR strains was reduced, most notably that of catalase activity at a salinity of 6 dS m-1, when compared with the control. The results indicate that co-inoculation with B. subtilis and Arthrobacter sp. could alleviate the adverse effects of soil salinity on wheat growth.