Growth kinetics, improved plant growth and alleviation of water stress in tomato by water stress tolerant bacteria

Plants are subject to a variety of abiotic stresses contributed to yield losses of up to 50%, posing a significant challenge to global food production. To cope with drought stress, of 205 bacterial cultures investigated for moisture stress tolerant potential, 16 cultures showed promising results in improving the majority of plant growth ameliorating activities under water stress and non-stress conditions. Growth kinetics and plant growth ameliorating activities declined significantly with the increase in water stress level. Most of the isolates tolerant to water stress were Streptomyces and Pseudomonas species. Of these, four strains with the best results were selected for growing tomato under water stress conditions. The imposition of water stress severely inhibited the growth of tomato plants. However, bacterial strains alleviated the stress and enhanced plant growth performance. Antioxidant activity showed a promising result of protection from reactive oxygen species produced in plants because of water stress. Plants treated with bioinoculants also exhibited a substantial decline in lipid peroxidation. Water stress significantly reduced the yield of tomato. However, bioinoculants treated plants demonstrated significantly higher yields than untreated plants. Nutrient uptake and fruit quality also improved in the treated plants. Experiments point to the scope of developing a microbial formulation to alleviate water stress in higher plants.