Honeybees, those tireless foragers, carry much more than just pollen when they visit flowers. Their precious harvests actually contain a microscopic army of beneficial bacteria that could revolutionize our approach to protecting hives and agricultural crops.
American researchers have focused their investigations on actinobacteria, a particularly promising microbial group since nearly two-thirds of antibiotics used in human medicine are derived from them. Between April and June 2021, the scientific team collected pollen samples from ten different plant species in the Lakeshore Nature Reserve, as well as from the reserves of a nearby bee hive. Genetic analysis revealed a surprising similarity between the bacterial strains from the plants and those found in the hive.
The study published in
Frontiers in Microbiology demonstrates that 72% of the identified bacteria belong to the
Streptomyces genus, known for producing compounds with remarkable medicinal properties. These microorganisms proved particularly effective during laboratory tests where they inhibited the growth of
Aspergillus niger, a fungus responsible for stonebrood disease in bees. They also showed significant activity against several bacterial pathogens affecting both pollinating insects and cultivated plants.
The transfer mechanism of these beneficial bacteria occurs naturally during foraging. Bees, when landing on flowers, inadvertently collect these endophytic microorganisms - bacteria that live in symbiosis inside plant tissues. Genomic analysis confirmed that these
Streptomyces indeed possess the necessary genes to colonize plants and produce substances that promote their growth, reinforcing their status as true biological partners.
This discovery opens exciting prospects for sustainable beekeeping. Researchers are now considering developing biological treatments based on introducing beneficial bacterial strains directly into hives. This approach could help control bee diseases without resorting to chemicals, while preserving the ecological balance of colonies and their environment.
Actinobacteria: natural antibiotic factories
Actinobacteria represent a particularly important group of bacteria in the microbial world. Their name comes from the Greek 'aktis' meaning ray, referring to their filamentous shape that resembles light rays when they grow in colonies.
These microorganisms are capable of producing an incredible diversity of bioactive molecules. Approximately 45% of all known antibiotics come from actinobacteria strains, making them the most productive source of antimicrobial substances in nature. Forest soil in particular contains remarkable concentrations of these beneficial bacteria.
Their mode of action relies on the secretion of secondary metabolites that inhibit the growth of other competing microorganisms. This ecological competition strategy explains why they naturally produce substances capable of neutralizing various pathogens, from fungi to harmful bacteria.
Researchers are constantly exploring new actinobacteria strains in various environments, from marine depths to deserts, hoping to discover new molecules with unprecedented therapeutic properties.