Pollen holds a secret that might save honeybees

A group of researchers from the US suspected {that a} wealthy new supply of ecofriendly remedies for bee illnesses is likely to be hiding in plain sight: within the pollen gathered by bees. They reasoned that so-called endophytes, symbiotic micro organism and fungi dwelling inside most plant tissues, ought to profit when their hosts are pollinated. This may very well be an incentive for these microbes to evolve compounds that maintain their host’s pollinators wholesome.

And now, they’ve proven their hunch to be right.

“We found that the same beneficial bacteria occur in pollen stores of honeybee colonies and on pollen of nearby plants,” stated Dr Daniel May, a college member at Washington College in Maryland, US, and the corresponding writer of a research in Frontiers in Microbiology.

“We also show that these bacteria produced similar antimicrobial compounds that kill pathogens of bees and plants, making them a great starting point for new treatments of crops and hives.”

Precious pollen

May and colleagues homed in on micro organism from the phylum actinobacteria, the supply of two-thirds of the antibiotics at the moment in scientific use. Between April and June 2021, they collected pollen from 10 native plant species within the Lakeshore Nature Preserve on the University of Wisconsin — Madison. They additionally collected pollen from the shops of a close-by honeybee hive.

The authors remoted 16 strains of actinobacteria from crops, and 18 strains from pollen shops contained in the hive. DNA barcoding and genome sequencing revealed that the identical or intently associated species occurred in each kinds of samples. The majority (72%) belonged to the genus Streptomyces, the supply of many compounds utilized in drugs and agriculture, for instance as antibiotics or as anticancer and antiparasitic medication. Some of the closest family members of the Streptomyces species discovered listed here are at the moment below research elsewhere as potential sources of compounds towards illnesses of crop crops.

The authors then performed ‘competitors assays’, the place recognized pathogens have been grown along with the Streptomyces remoted right here. Nearly all of those proved to be efficient inhibitors of the mould Aspergillus niger, which might trigger a honeybee illness referred to as stonebrood. Individual strains additionally proved reasonably to strongly energetic towards two bacterial pathogens of honeybees, Paenibacillus larvae and Serratia marcescens, and towards three pathogens of crops, Erwinia amylavora, Pseudomonas syringae, and Ralstonia solanaceum.

‘Whisked again to the hive’

“We isolated the same Streptomyces bacteria from flowers, pollen-covered bees leaving flowers, and hives. We conclude from our results that endophytic actinobacteria on pollen grains are picked up by pollinating bees and whisked back to hive pollen stores, where they help to defend the colony against disease,” stated May.

The authors discovered clear proof within the genome of the sequenced species that they have been certainly endophytes, moderately than dwelling in a free, haphazard affiliation with crops. They possessed genes encoding enzymes that enable Streptomyces to colonize plant tissue, produce hormones to spice up the expansion of their host, or scavenge metals round roots.

The outcomes confirmed that an excellent number of fascinating bioactive compounds stay to be found in endophytes, lots of which may assist us to maintain honeybees wholesome. They additionally counsel {that a} panorama wealthy in plant species is helpful for bees, because it ensures a larger variety of actinobacterial endophytes accessible to them.

“In the future, treating bee diseases could be a matter of simply introducing the right beneficial bacteria into hives to help control specific pathogens,” concluded May.