Genetically engineered gut bacterium could protect bees from parasite

A genetically engineered intestine bacterium has helped shield honeybees from a significant hive parasite in lab experiments. The bacterium produces RNA molecules that swap off two key genes within the parasite however don’t have an effect on some other organisms.

Nosema ceranae is a single-celled fungus that infects cells in honeybees’ guts utilizing a harpoon-like weapon. Contaminated cells launch spores that the bees defecate. Parasite ranges sometimes construct up over winters when unhealthy climate retains honeybees inside hives, and might kill many employees. “It’s a actually vital parasite,” says Nancy Moran on the College of Texas at Austin.

The one therapy proven to be efficient is a fungicide referred to as fumagillin, however it might probably hurt bees and different animals and is now banned within the European Union. What’s extra, Nosema is evolving resistance to it.

Moran has been creating safer therapies primarily based on a phenomenon referred to as gene silencing or RNA interference (RNAi). When cells detect bits of double-stranded RNA, they see it as a viral assault and reply by destroying RNAs that include an identical sequence. Meaning the protein coded for by these particular RNAs doesn’t get made.

Double-stranded RNA is quickly destroyed in mammalian guts, however in some bugs it might probably enter cells and swap off, or silence, particular genes. That has led to hopes of creating RNAi-based pesticides which might be solely dangerous to the goal organism, however one drawback is that making massive portions of RNA is pricey.

So Moran’s staff has as a substitute engineered a symbiotic intestine bacterium referred to as Snodgrassella alvi, discovered solely in bees, to supply the double-stranded RNA. In 2020, they confirmed that this method will help shield in opposition to varroa mites and deformed wing virus.

Now the staff has tailored the method to focus on two key Nosema genes, stopping spore manufacturing in contaminated cells. Seven days after honeybees within the lab had been intentionally contaminated with Nosema, solely 19 per cent of these within the management group had been nonetheless alive, in contrast with 71 per cent of these fed the engineered S. alvi. The handled bees additionally produced greater than 90 per cent fewer spores.

It ought to be potential to create a single S. alvi that protects in opposition to Nosema, varroa and deformed wing virus, Moran says. She now hopes to point out that hives given such engineered micro organism do higher than others. However such a research must be performed in sealed greenhouses, and the staff doesn’t have such services.

Moran doesn’t assume altered S. alvi would persist indefinitely in hives. “Virtually all the time, an engineered factor doesn’t final eternally as a result of it’s not as aggressive because the factor with out the engineering,” she says.