The widespread and prolonged application of chemical fungicides in crop protection has led to numerous environmental, economic, and social issues, most notably the development of fungicide-resistant pathogen strains. Driven by these concerns, agrichemical companies are increasingly committed towards the development of new emerging technologies, such as biological fungicides (biofungicides). Biological control offers sustainable, cost-effective pathogen suppression that acts via a range of biological modes of action. Despite their promise, the long-term efficacy and resistance management of biofungicides remain under-researched, prompting this study to investigate their durability.
In collaboration with INRAe (France) and USDA (USA), our research involved the high-throughput screening of an innovative Actinobacteria-derived biofungicide developed by CSIRO. This biofungicide was screened for efficacy against a genetically diverse collection comprising 200 strains of fungal pathogens, including those known to have developed resistance against chemical fungicides. These strains were obtained from both agricultural and non-agricultural settings in France and the USA, with several subjected to comprehensive genotypic and phenotypic characterization.
Findings revealed differential sensitivities to the biofungicide within a Botrytis population, indicative of natural resistance mechanisms. Ongoing research is focused on decoding the genetic diversity within B. cinerea populations and pinpointing genetic markers associated with differential sensitivities, crucial for elucidating the functional modes of action of biocontrol agents and the potential mechanisms by which pathogens may evade. Our research emphasises the need for global initiatives to incorporate insights on biocontrol durability into the development of future biological products, ensuring their effectiveness and extended lifespan for more sustainable crop protection practices.