Effect of Sole and Consortium Application of Endophytic Bacteria on Plant Growth Promotion and Inhibition of Meloidogyne incognita Infection in Okra

Abstract

Plant-parasitic nematodes (PPNs) are a serious threat to food security. Root-knot nematodes (RKNs) are important plant parasitic nematodes that affect vegetable crops worldwide including okra. Among the RKNs, Meloidogyne incognita [(Kofold and White) Chitwood] is one of the major constraints to okra production. In this study, the effect of different bacterial strains i.e., Bacillus sp. MN54, Enterobacter sp. MN17 and Burkholderia. phytofirmans PsJN alone and in different combinations was assessed on plant growth promotion and inhibition of M. incognita infection on okra in a greenhouse experiment under completely randomized design (CRD). The results revealed that application of Enterobacter sp. MN17 significantly enhanced the root length (19.0), root weight (8.7), and shoot dry weight (19.6) as compared to other treatments. However, the combined treatment of Bacillus sp. MN54 + Enterobacter sp. MN17 + B. phytofirmans PsJN has successfully reduced the number of galls (10.5), number of females (23.2), egg masses (19.5), egg mass index (4.1), and galling index (2.1) against the RKNs. Conclusively, the combined application of all the bacterial strains was more effective in causing the suppression of RKNs and promotion of plant growth. This study illustrates the role of endophytic bacteria in controlling root knot nematode infection through the different changes in plants.