Bio-nematicidal activities by culture filtrate of Bacillus subtilis HussainT-AMU: new promising biosurfactant bioagent for the management of Root Galling caused by Meloidogyne incognita

Abstract

Root galling caused by Meloidogyne incognita causes dramatic yield reduction in a wide range of crops, especially vegetables, at most 15–25%, however, in severe cases it can reach upto 75%. A new biosurfactant bacteria characterized through 16S rRNA gene sequencing and biochemically as Bacillus subtilis HussainT-AMU that was isolated from oil contaminated soil from Odisha coat line near Paradip port exhibiting significant biosurfactant activity in all screening assays. Most of the in vitro experiments were carried out at room temperature. Exposure of fresh culture filtrate from new bioagent to M. incognita caused substantial mortality of the second stage juvenile (J2) and significantly reduced egg hatchability. 100% of culture filtrate collected from B. subtilis HussainT-AMU caused J2 mortality and reduced hatching (p < 0.05). Hatching was defective by 97–99%. More than 90% J2 mortality occurred after 24 h of exposure in 100%. Significant reduction (58.79%) in number of galls/plant in tomato roots in combined application leading to reduction in root galling was recorded. This novel biosurfactant bacterial strain seems to be a safe and effective bio-nematicide potential that needs to be explored more both at field study as well genomic level.