Meloidogyne incognita is one of the most destructive plant-parasitic nematodes worldwide, causing severe economic losses in agricultural production. Biocontrol bacteria can effectively control M. incognita , with significant differences in control efficacy among different strains. However, the mechanisms underlying differences in control efficacy remain unclear.
A team of plant nematode scientists led by Wei Qiu from Zhejiang A & F University in Hangzhou, China recently explored the mechanisms responsible for the different efficacy of various biocontrol bacteria against nematodes. The differences in nematicidal activity between two biocontrol bacterial strains, B133 and B104, were analyzed. Comparative genomics and metabolomics techniques were employed to investigate the genetic composition and metabolic mechanisms influencing the nematicidal activity of the two strains. By coupling genomics and metabolomics, this study reveals the different functional gene clusters and potential related metabolites of different subspecies of P. megaterium , laying a theoretical foundation and a practical basis for the targeted screening, modification, and industrial development of efficient biocontrol agents for nematodes.
The team published their research in Acta Microbiologica Sinica on June 30, 2026.
“In this study, we systematically dissect the nematicidal functional differences between two P. megaterium strains, B133 and B104, against Meloidogyne incognita , along with their underlying molecular mechanisms. Our analysis centers on genomic features, metabolite profiles, and gene-metabolite association pathways. Furthermore, we investigate the possibility that subspecies-level genomic structural variations may serve as key drivers of the functional divergence in biocontrol efficacy.” said Wei Qiu, senior author of the research paper, lecturer in the College of Environment and Resources/College of Carbon Neutrality, Zhejiang A&F University.
P. megaterium , as a key biocontrol resource within the genus Priestia , offers advantages such as rapid growth and abundant metabolite production, making it an excellent candidate strain for developing biocontrol agents against root-knot nematodes.
Through integrative multi-omics analysis, the research team revealed that although the two strains belong to different subspecies of P. megaterium and share highly conserved core genomic features, their genomes exhibit structural variations, including inversions and translocations. Moreover, strain B133 carries 22 unique virulence factor genes and 75 unique metabolic genes, which constitute the genetic basis underpinning its enhanced nematicidal function.
Untargeted metabolomic analysis further revealed significant differences in the metabolite profiles of the fermentation broths between the two bacterial strains. Specifically, 40 metabolites, including galactinol, aminobenzoic acid, lumichrome, trehalose, and 3-(methylthio) propionic acid, were significantly enriched in the B133 filtrate. Dr. Qiu said, “These metabolites possess direct nematicidal activity, among which 3-(methylthio) propionic acid was positively correlated with nematicidal activity and served as the core functional metabolite regulating the biocontrol efficacy.”
The research team anticipates that the outcomes of this study will facilitate the precise screening and genetic engineering of biocontrol bacteria against root-knot nematodes, thereby accelerating the industrial-scale production and commercial deployment of efficient, stable, and environmentally friendly bacterial biocontrol agents. Wei Qiu said, "The functional differences among closely related biocontrol bacteria are jointly determined by genetics and metabolism. Uncovering strain-specific genes and core metabolites can precisely overcome the bottleneck of inconsistent efficacy that currently plagues biocontrol agents. In the future, targeted optimization based on these key genes and metabolites will further enhance the control efficacy of P. megaterium against M. incognita , contributing to the sustainable development of green agriculture."
ACTA MICROBIOLOGICA SINICA
Differences in nematicidal function and mechanisms between two strains of Priestia megaterium
4-Jul-2026