Salinity stress mitigation on Zea mays L. seedling by halotolerant bacteria

Abstract

Halotolerant bacteria are reported as a potential biostimulant to mitigate saline stress on various crops. The mechanism of halotolerant bacteria in elevating plant growth under saline stress is associated with their plant growth-promoting (PGP) traits. This study evaluated the activity of single-strain halotolerant phosphate-solubilizing bacteria and its consortia with halotolerant bacteria that were able to fix nitrogen and produce ACC deaminase in alleviating salinity stress on Zea mays seedlings under in vitro conditions. One single strain and five consortia of bacterial isolates were tested for seedling growth assay under four salinity levels (0, 60, 80, and 100 mM). In vitro assay showed that halotolerant bacteria B1 (Vibrio alginolycticus) and all consortia significantly increased root number at 60 mM salinity level. Consortium B3 (V. alginolyticus+Salinicola zeshunii) was also able to improve the fresh weight of seedlings significantly (by 63.3%). Moreover, inoculation of consortium B3 affected more proline and soluble sugar accumulation in Z. mays seedlings when compared to uninoculated seedlings. We conclude that the application of a consortium of halotolerant bacteria V. alginolyticus+S. zeshunii was potentially used in improving Z. mays growth in slightly and moderately saline areas.