Isolation and Characterization of Novel Biological Control Agent Clostridium beijerinckii against Meloidogyne incognita

SIMPLE SUMMARY: Meloidogyne incognita is one of the most widely distributed and researched species of Meloidogyne, which has caused enormous economic losses for Chinese agriculture. Biological control is a nonhazardous method of pest and pathogen management. Nematophagous bacteria, which are ubiquitous and have extensive host ranges, are an efficient natural adversary of nematodes. Thus, to find novel, promising biological control agents for RKNs, we conducted trials to isolate and screen effective bacterial endophytes against M. incognita, and then we selected an effective strain using morphological and molecular approaches. Furthermore, a greenhouse experiment was conducted to assess their potential as biocontrol agents against M. incognita and to investigate the effect of several strains on increasing seed germination and tomato plant growth. Strain Sneb518 (Clostridium beijerinckii) was identified as having solid biocontrol activity against M. incognita. Sneb518 demonstrated significant inhibition against M. incognita, with J2 mortality reaching 90.73% at 12 h and with eggs hatching at a rate of 6.00% at 24 h. Additionally, Sneb518 was excellent for enhancing seed germination. The effectiveness and stability of M. incognita management by Sneb518 C. beijerinckii were further evaluated in a greenhouse. This research will offer insightful information on the application of Sneb518 as a biocontrol agent for RKN management. ABSTRACT: One of the most severe soil-borne pathogens in the world is the root-knot nematode (Meloidogyne incognita). Biological control is gaining more importance as environmental awareness increases. Thus, keeping this in mind, a total of 712 bacterial strains were isolated from 117 rhizosphere soil samples and investigated for potential biological control activity against M. incognita. Strain Sneb518 (Clostridium beijerinckii) was identified as having solid biocontrol activity against M. incognita. Sneb518 demonstrated significant inhibition against M. incognita, with J2 mortality reaching 90.73% at 12 h and with eggs hatching at a rate of 6.00% at 24 h, compared to a hatchability level of 29.07% for the control. Additionally, Sneb518 was excellent for enhancing seed germination. The seeds coated with a fermentation broth containing Sneb518 efficiently boosted the germination rate to 88.49%. The effectiveness and stability of C. beijerinckii Sneb518 against M. incognita were then further evaluated in a greenhouse. According to the pot experiment data, Sneb518 considerably (p < 0.05) reduced the number of root galls and egg masses on roots and also significantly (p < 0.05) increased tomato plant growth. C. beijerinckii Sneb518-treated tomato seedlings exhibited 50.26% biocontrol effectiveness compared to the control group. Our results demonstrate that C. beijerinckii Sneb518 can be a potential biological control agent against root-knot nematode disease and a biomass enhancer. This research will give new options for the sustainable control of root-knot nematode disease in tomatoes and other host plants.