Species of probiotic Bacillus bacteria have demonstrated promise as a biological control agent against the pathogen which causes the highly-destructive disease wheat blast.
Researchers at the Institute of Biotechnology and Genetic Engineering in Bangladesh used bacterial cultures to select promising candidates from 170 bacterial isolates, and then tested the selections on seedlings infected with Magnaporthe oryzae Triticum (MoT).
MoT is a fungal pathogen considered to be a major threat to global wheat production, with losses over 50% in infected fields. To date, cases have been identified in South America and South Asia.
In the greenhouse experiments, seedlings were sprayed with 100ml solutions of the three most promising Bacillus isolates. The intervention resulted in 89, 88 and 85% reductions in disease severity, and were later identified as B. subtilis and B. velezensis.
Further analysis using whole genome sequencing showed genes linked with antimicrobial activity, enzymes which degrade cell walls, antioxidants and systemic resistance.
Wider applications needed
Although the early results are promising, better understanding of performance, as well as a scaling up of testing, are still required before the Bacillus strains can be considered a commercially-viable option.
“Further studies are needed to precisely identify the specific genes involved in the production of antimicrobial substances and also characterize the structural features of the chemical arsenals produced by those bacteria,” the researchers said.
“A large-scale field evaluation of the efficacy of biocontrol bacteria at reproductive stage of wheat is needed before recommending them for practical use as biocontrol agents against wheat blast fungus.”
