Host-Mediated Selection of Drought-Tolerant Rhizobacteria: Enhancing Growth, Yield, and Nutritional Quality of Solanum lycopersicum L. under Dry-Season Cultivation

Abstract

Tomato (Solanum lycopersicum L.) is one of the world’s most consumed vegetables. Water stress arising from climate change is a major setback in tomato cultivation. This study aimed to isolate drought-resistant rhizobacteria through novel host-mediated artificial selection and to evaluate their influence on tomato growth. Tomato seeds were planted in pots under water stress conditions to screen and select rhizobacteria associated with healthy plants. Their influence on growth and yield of tomatoes was assessed on the field during the dry season. The effect of the treatments on some nutrient contents of harvested tomatoes was also evaluated. Tomato plants subjected to soil microbiota under drought stress significantly (P ≤ 0.05) delayed the onset of tomato plant wilting by 3, 5, 6 and 8 days, respectively from the 1st to the 4th round of microbiota selection. Four strains genetically identified as Bacillus cereus AN14, B. thuringiensis AN10, B. mycoides ANP and B. tropicus AN22 produced varying growth-promoting substances in-vitro and significantly enhanced agronomic parameters than the controls during field trials. Microbiota and B. cereus AN14, which had the most effective agronomic effects, have no significant influence on the tested nutritional components of tomatoes. These bioinoculants can compete with in-situ microorganisms to promote growth and yield of tomatoes during dry-season cultivation.