Singh, A., Microbial Technology and Nematology Department, CSIR- Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, India; Srivastava, M., Analytical Chemistry Department, CSIR- Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, India; Shanker, K., Analytical Chemistry Department, CSIR- Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, India; Pandey, R., Microbial Technology and Nematology Department, CSIR- Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, India

The modification of rhizosphere microbial diversity and ecological processes are of rising interest as shifting in microbial community structure impacts the mutual role of host–microbe interactions. Nevertheless, the connection between host-microbial community diversity, their function under biotic stress in addition to their impact on plant performances is poorly understood. The study was designed with the aim to analyze the tripartite interactions among Chitiniphilus sp., Streptomyces sp. and their combination with indigenous rhizospheric microbial population of Bacopa monnieri for enhancing the plant growth and bacoside A content under Meloidogyne incognita stress. Overall, plants treated with the microbial combination recorded enhanced growth as illustrated by significantly higher biomass (2.0 fold), nitrogen uptake (1.8 fold) and bacoside A content (1.3 fold) along with biocontrol efficacy (58.5%) under nematode infected field. The denaturing gradient gel electrophoresis (DGGE) fingerprints of 16S-rDNA revealed that microbial inoculations are major initiators of bacterial community structure in the plant rhizosphere. Additionally, the plants treated with microbial combination showed maximum diversity viz., Shannon's (3.29), Margalef's (4.21), and Simpson's (0.96) indices. Likewise the metabolic profiling data also showed a significant variation among the diversity and evenness indices upon microbial application on the native microflora. We surmise that the application of beneficial microbes in combinational mode not only helped in improving the microbial community structure but also successfully enhanced plant and soil health under biotic stress. © 2018