Sodium-resistant plant growth-promoting rhizobacteria isolated from a halophyte, Salsola grandis, in saline-alkaline soils of Turkey

Abstract

Phytoremediation is an expanding field of research in environmental studies due to the benefits of its cost effectiveness and environmental friendliness. The use of this technology in saline and alkaline soils can be a promising approach because soil salinity inhibits crop growth and causes tremendous yield losses in many regions of the world, especially in arid and semi-arid regions. However, little is known about the plants that can be applicable in the phytoremediation of saline soils and role of their rhizobacteria in the phytoremediation processes. In this study, we examined sodium (Na) uptake by the halophyte Salsola grandis and screened Na resistant rhizobacteria inhabiting in an extremely saline soil environment. S. grandis could uptake Na at the value of 15447 mg · kg -1 and transported Na to stem and leaves from roots. We found that 50 out of the 131 strains were Na resistant and 8 out of these 50 strains contributed to the growth of S. grandis . Using 16S ribosomal RNA sequencing, we determined these eight strains to be within the genera Arthrobacter spp. and Bacillus spp. Moreover, four of the eight strains (A22, WP5, B14, AP20) showed traits of being both siderophore and indole-3-acetic acid producers. Therefore, these eight strains appear to be suitable candidates for plant growth-promoting rhizobacteria of S. grandis .