Assessing the efficacy of climate resilient microbial inoculants for enhanced phytochemical production from Indian licorice (Abrus precatorius L.)

Chemical fertilizers adversely affect beneficial micro-organism of the soil with high residual contamination in the plants which subsequently raises questions on the quality of useful metabolites of medicinal plants. The study investigates the efficacy of plant growth-promoting microbes, i.e., Bacillus pseudomycoides RS6B, Bacillus firmus RS7B, Aspergillus luchuensis RS6F, and Aspergillus tamarii RS8F, individually as well as in consortium on growth and glycyrrhizic acid content of Indian licorice (Abrus precatorius L). The maximum increase in biomass of root, stem, and leaves was obtained as 2.48 folds, 2.40 folds, and 2.41 folds along with 4.95, 4.63 and 2.61 folds in glycyrrhizic acid content, respectively on the rhizo-engineering of the consortium of all the 4 microbes. The microbial inoculants also increased soil organic carbon (1.44 times), available phosphorus (3.06 times), and microbial biomass carbon (3.01 times) in the soil after 120 DAS over non inoculated control. It appears that the microbial consortium of these 4 PGPMs is a highly efficient growth promoter over no microbes and individual PGPM for Indian licorice. It can be developed as a potential bioinoculant for the ecological cultivation of this important and commercial medicinal plant.