Scientists in Mexico have discovered a new species of bacterium which could ultimately prove a useful addition to growers’ sustainable pest control arsenal.
The researchers isolated the novel species, which has initially been named Bacillus mexicanus sp. nov., from the roots of common bean (Phaseolus vulgaris) plants.
They determined that it is distinct from previously identified species through genetic sequencing and in-depth analysis of its traits, and also observed that the isolated strain of the species, named FSQ1, showed biological control potential against the fungus Sclerotinia sclerotiorum, which causes the common crop disease white mould.
They then screened the isolate to establish which of its genes are related to biological control, finding three gene clusters of interest. These were rhizocticin A, a natural antibiotic, bacillibactin, which removes iron from the environment, making it uninhabitable for many pathogens, and surfactin, a peptide which is known to have antifungal, antitumour and insecticidal properties.
Deep understanding of biocontrols needed
“Despite the great scientific advances in plant growth promoting bacteria and and biological control agents and their wide commercialisation, little is known about these active ingredients at a species level in bioformulations,” the scientists wrote in International Journal of Systematic and Evolutionary Microbiology.
“Thus, a shallow taxonomic analysis may result in misidentified species, potentially leading to the development of biofertilizers or biopesticides using potentially hazardous bacterial strains.”
Underlining their point, the scientists noted that there are significant distinctions between different Bacillus species. Bacillus thuringiensis, for example, is used globally as a successful biopesticide, while Bacillus anthracis is a pathogen which threatens humans and herbivorous animals.
“It is important not only to explore and discover beneficial bacterial strains for agriculture but also to ensure that biopesticides include fully taxonomically identified active ingredients at the species or subspecies level. This will ensure the safe and effective application of these products in agroecosystems,” they stressed.
Identification of the new species is the first of several possible steps before B. mexicanus can be employed as a commercial product in the field — but it serves as a reminder of the abundance of potential natural sources of pest control agents, and the importance of ensuring their potential impacts in the field are fully understood.
