Actinobacteria as biological nitrogen fixation (BNF) and symbiotic association with actinorhizal plants for restoration of salinized soils

Abstract

Soil salinity is a significant environmental problem affecting agricultural productivity worldwide. Salinized soils are one of the highest exchangeable sodium salts present in zone of the roots. In this scenario, much focus was drawn towards the symbiotic association between the plant species and the nitrogen fixing actinobacterial species. Actinobacteria are well known for their ability to produce secondary metabolites with potential applications in bioremediation and plant growth promotion. This study investigated the efficiency of co-culturing with actinobacteria to enhance the growth of plants under 0.5% NaCl conditions. Pot trials were conducted with three different treatments, fertile soil without actinobacteria, 0.5% NaCl mixed soil with actinobacteria co-culturing, and 0.5% NaCl mixed soil without actinobacteria co-culturing. The results showed that the plants grown in the 0.5% NaCl mixed soil with actinobacteria co-culturing treatment exhibited significantly plant growth, compared to the other two treatments. The co-culturing of actinobacteria was found to improve the plant's ability to tolerate high salinity conditions and enhance their growth. In this study, actinobacteria were isolated from high saline soil samples using selective media, and their morphological and biochemical characteristics were examined.