Potential of Bacillus altitudinis KMS-6 as a biocontrol agent of Meloidogyne java']javanica

Root-knot nematodes are among the most dangerous plant pathogens. Biological control is a safer and effective way to manage such pests. In this context, bacterial strain KMS-6 was isolated from nematode-affected soil of the research field, CCS HAU, Hisar. It was subjected to morphological and biochemical characterization. The bacterium produced 14.02 +/- 0.03 mu g/ml of IAA and showed a cyanogenic activity. KMS-6 was identified based on 16S rRNA gene sequence analysis as Bacillus altitudinis (accession no. MT626660). In vitro experiments with fermentation supernatants of KMS-6 resulted in potential hatching inhibition and up to 86% J2s mortality of M. javanica. The bacterium significantly suppressed root-knot nematode infestations in greenhouse and field experiments. During the greenhouse experiment on eggplant, KMS-6 inoculation resulted in a 76% reduction in eggs, 80% reduction in galls, reducing the final nematode population up to 92% compared to control. All trials were significantly more effective than the chemical treatment as well. Also, an enhancement in plant growth was observed in KMS-6 inoculated plants with the highest plant height, maximum fresh and dry weight of root and shoot. Similar results were seen in trials conducted on eggplant (2018) and cucumber (2019) crops in nematode-infested fields. KMS-6 inoculation reduced nematode infestation more effectively than control and carbofuran treatments. The yield was significantly improved in the KMS-6 treatment. Data suggest that B. altitudinis KMS-6 could be an effective biological control agent with plant-growth enhancing properties against root-knot nematodes and a potent alternative to chemical nematicides.