HALOTOLERANT PHOSPHATE SOLUBILIZING IAA–SYNTHESIZING REPRESENTATIVES OF PANTOEA GENUS PROMOTE PROLINE SYNTHESIS IN WHEAT SEEDLINGS UNDER SALT STRESS

Two halotolerant bacterial strains A1 and A15 of Pantoea genus were isolated from the plants growing in saline soils near the waste banks of Solikamsk technogenic biotope (Perm krai, Russia). Microorganisms were able to produce indole-3-acetic acid (IAA) from L-tryptophan and solubilize insoluble phosphates. Maximum accumulation of IAA occurred at the stationary growth phase. In the experiment with wheat seedlings inoculated with isolated strains under salt stress condition, proline concentrations in fresh weight on day 3 were 3 and 2.4 times higher than the control ones reaching 616 and 485 µg/g for A1 and A15 with 1% NaCl respectively. However the higher values of protein content in the variants with salt were achieved only within 7 days, accounting 113% and 138% of the respective total protein amount in the control with 1% of salt for A1 and A15 respectively.