Biofilm formation as an extra gear for Apilactobacillus kunkeei to counter the threat of agrochemicals in honeybee crop

Abstract

The alteration of a eubiosis status in honeybees' gut microbiota is directly linked to the occurrence of diseases, and likely to the honeybees decline. Since fructophilic lactobacilli were suggested as symbionts for honeybees, we mechanistically investigated their behaviour under the exposure to agrochemicals (Roundup, Mediator and Reldan containing glyphosate, imidacloprid and chlorpyrifos-methyl as active ingredients respectively) and plant secondary metabolites (nicotine and p-coumaric acid) ingested by honeybees as part of their diet. The effects of exposure to agrochemicals and plant secondary metabolites were assessed both on planktonic cells and sessile communities of three biofilm-forming strains of Apilactobacillus kunkeei. We identified the high sensitivity of A. kunkeei planktonic cells to Roundup and Reldan, while cells embedded in mature biofilms had increased resistance to the same agrochemicals. However, agrochemicals still exerted a substantial inhibitory/control effect if the exposure was during the preliminary steps of biofilm formation. The level of susceptibility resulted to be strain-specific. Exopolysaccharides resulted in the main component of extracellular polymeric matrix (ECM) in biofilm, but the exposure to Roundup caused a change in ECM production and composition. Nicotine and p-coumaric acid had a growth-promoting effect in sessile communities, although no effect was found on planktonic growth.

The effects of urban land use gradients on wild bee microbiomes

“…Apilactobacillus , Alternaria , Penicillium and Ascosphaera were the most prevalent and abundant bacterial and fungal genera found across the city ( Supplementary Tables S2, S3 ). Apilactobacillus are common beneficial bee symbionts ( Tlais et al, 2022 ) and were established as part of the core microbiome in C. calcarata in New Hampshire, a more rural landscape ( McFrederick and Rehan, 2016 ; Graystock et al, 2017 ). In urban cities such as Toronto, Apilactobacillus was previously largely absent in adult C. calcarata ( Nguyen and Rehan, 2022 ) and was found to be underrepresented at sites with moderate levels of land use development, overrepresented in sites with the most green space, and overrepresented at sites with lower annual temperatures in this study ( Supplementary Table S4 ).…”

Fermented Whey Ewe’s Milk-Based Fruit Smoothies: Bio-Recycling and Enrichment of Phenolic Compounds and Improvement of Protein Digestibility and Antioxidant Activity

“…To fully exploit the metabolic potential of LAB, the strains were chosen according to their environment of origin and ensuring a high degree of heterogeneity in terms of metabolism patterns. LAB strains were previously isolated from fruit and milk whey (data not published), with the exception of fructophilic lactic acid bacteria (FLAB) Apilactobacillus kunkeei BEE4, which was isolated from the gastro-intestinal tract of bees [25] (Table S1). Cultures were maintained as stocks in 20% (v v −1 ) glycerol at −20 • C and routinely propagated at 30 • C for 24 h in MRS broth (Oxoid, Basingstoke, Hampshire, UK) for LAB and in FYP broth for FLAB.…”

Multi‐host lifestyle in plant‐beneficial bacteria: an evolutionary advantage for survival and dispersal?

“…Fructophilic lactobacilli form biofilms in honeybee hosts and previous studies revealed that organophosphorous pesticides have negative impacts on the honeybee microbiome (Motta and Moran, 2020). Tlais et al (2022) found that biofilm-forming A. kunkeei strains are more resistant to glyphosate and chlorpyrifosmethyl, while further studies are required to determine whether these bacteria have beneficial effects on honeybees when exposed to agrochemicals.…”

“…Yet, pollen and nectar often contain bioactive plant secondary metabolites (Schmitt et al ., 2021) as well as agrochemicals that can alter the insect microbiome composition. As a means to understand the role of specific bacterial taxa on honeybee health, a recent report in Microbial Biotechnology explored the effects of different agrochemicals and plant secondary metabolites on planktonic and biofilm growth of fructophilic lactobacilli isolated from both the gut of honeybees and bee‐collected pollen (Tlais et al ., 2022). The study found that the organophosphorus pesticides glyphosate and chlorpyrifos‐methyl completely inhibited planktonic growth of Apilactobacillus kunkeei strains, a fructophilic lactobacilli species that is a frequent inhabitant of honeybees, and drastically affected their abilities to form biofilms.…”

“…Tlais et al . (2022) found that biofilm‐forming A . kunkeei strains are more resistant to glyphosate and chlorpyrifos‐methyl, while further studies are required to determine whether these bacteria have beneficial effects on honeybees when exposed to agrochemicals.…”