Engineered symbiotic bacteria interfering Nosema redox system inhibit microsporidia parasitism in honeybees

Abstract

Nosema ceranae is an intracellular parasite invading the midgut of honeybees, which causes serious nosemosis implicated in honeybee colony losses worldwide. The core gut microbiota is involved in protecting against parasitism, and the genetically engineering of the native gut symbionts provides a novel and efficient way to fight pathogens. Here, using laboratory-generated bees mono-associated with gut members, we find that Snodgrassella alvi inhibit microsporidia proliferation, potentially via the stimulation of host oxidant-mediated immune response. Accordingly, N. ceranae employs the thioredoxin and glutathione systems to defend against oxidative stress and maintain a balanced redox equilibrium, which is essential for the infection process. We knock down the gene expression using nanoparticle-mediated RNA interference, which targets the γ-glutamyl-cysteine synthetase and thioredoxin reductase genes of microsporidia. It significantly reduces the spore load, confirming the importance of the antioxidant mechanism for the intracellular invasion of the N. ceranae parasite. Finally, we genetically modify the symbiotic S. alvi to deliver dsRNA corresponding to the genes involved in the redox system of the microsporidia. The engineered S. alvi induces RNA interference and represses parasite gene expression, thereby inhibits the parasitism significantly. Specifically, N. ceranae is most suppressed by the recombinant strain corresponding to the glutathione synthetase or by a mixture of bacteria expressing variable dsRNA. Our findings extend our previous understanding of the protection of gut symbionts against N. ceranae and provide a symbiont-mediated RNAi system for inhibiting microsporidia infection in honeybees.

Experimental evidence and meta-analysis indicate the negative effect of nosemosis on the survivorship of honeybees

“…Significant attention is paid to the application of Good Beekeeping Practices as a form of prevention (Formato et al 2022). However, while these methods yield some results, they still prove insufficient (Huang et al 2013, Holt and Grozinger 2016, Garrido et al 2023, Lang et al 2023, Prouty et al 2023). There is a pressing need for further research on N. ceranae , especially in the context of its effective control strategies that consider the microbiological safety of the hive products (i.e.…”

Effects of Active Ingredients in Alcoholic Beverages and Their De-Alcoholized Counterparts on High-Fat Diet Bees: A Comparative Study

“…The bee gut microbiota comprises nine bacterial clusters, which represent 95% to 99.9% of all individual bacteria, including Snodgrassella alvi of the β-Proteobacteria, Gilliamella apicola of the γ-Proteobacteria, Bombilactobacillus Firm-4 and Firm-5 in the phylum Bombilactobacillus of the Firmicutes phylum, and Bifidobacterium spp. of the genus Actinobacteria [15]. Unlike humans, mice, and other animals, bees have Firmicutes, Proteobacteria, and Actinobacteria as the main dominant phyla in their gut microbiota, which play a crucial role in maintaining metabolic homeostasis.…”

An engineered bacterial symbiont allows noninvasive biosensing of the honey bee gut environment

“…More importantly, the microbial community residing in the gut of honey bees has been formally described only recently [26,27]. The first report of a functional molecular tool kit for these bacterial species was just published 5 years ago, and it was later remarkably used to reprogram a bee gut symbiont to promote health of its host, as well as to regulate bee gene expression by symbiont-mediated RNAi [28][29][30][31]. More recently, a new method based on homologous recombination allowed for one-step genomic knock-out and knock-in in a honey bee gut bacterium [32].…”