Isolation, characterization, and field evaluation of Lactic Acid Bacteria (LAB) as plant growth promoting agents in tomato (Solanum lycopersicum L.) Cultivation

Abstract

The present study explored the isolation, characterization, and functional evaluation of lactic acid bacteria (LAB) from curd samples collected from four villages of Rahuri Taluka, Ahmednagar, Maharashtra. Four distinct LAB strains (CRD-I, CRD-II, CRD-III, CRD-IV) were purified and subjected to morphological, biochemical, and phenotypic characterization, confirming typical Lactobacillus spp. traits, including Gram-positive rods, fermentative metabolism, and broad carbohydrate utilization. Functional screening revealed significant variation among isolates, with CRD-II (Rahuri) demonstrating the highest lactic acid production (7.40%), superior phosphate solubilization, and enhancement of tomato seed germination. A field trial under a randomized block design assessed the effect of LAB inoculation combined with graded NPK levels and foliar application. Integrated treatments significantly improved plant survival, height, branching and yield.