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 genetic 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 inhibited 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 knocked 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 modified 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 parasitism by up to 99.8%. Specifically, N. ceranae was 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.

Identification of peptides from honeybee gut symbionts as potential antimicrobial agents against Melissococcus plutonius

“…Additionally, adult workers removing infected larvae may transfer pathogens to healthy broods within colonies 67 and even between colonies through robbing and drifting 68 . Erban et al 12 showed that M. plutonius reached ~10 6 CFU/bee in the adult bees from colonies with clinical symptoms, which is 75-fold-higher than those from asymptomatic colonies. Our results showed that gnotobiotic bees mono-colonized with G. apis stain B14384H2 can achieve ~100-fold reduction of M. plutonius (on average, from 2.12 × 10 8 to 6.22 × 10 6 , p = 0.0079).…”

“…The colony loss has been described as multifactorial, involving combinations of environmental stress and infectious agents 3,4 . Honeybees are susceptible to various biological agents that cause disease, including eukaryotic 5,6 and prokaryotic pathogens 7 . Bacterial diseases are a significant contributing factor to the colony collapse disorder of honeybee populations 2 .…”

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 Nosemosis and mortality in honeybees Practices as a form of prevention (Formato et al 2022). However, while these methods yield some results, they still prove insufficient , 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.…”

Identification of odorant‐binding proteins and functional analysis of antenna‐specific BhorOBP28 in Batocera horsfieldi (Hope)

“…Utilizing engineered symbionts or bacteria to express and deliver dsRNA is an effective strategy for mediating insect physiological activities. 54,55 However, few studies have focused on mediating insect behavior through bacterial delivery of dsRNAs. A previous study of OBP from M. alternatus showed that feeding bacteria-expressed dsRNA can significantly repress the expression of OBP19 in adult M. alternatus.…”