Scientists engineer bacteria to protect bees against pests and virus infections

Researchers have engineered new strains of bacteria to protect honey bees from a deadly trend known as the colony collapse disorder -- a global phenomenon in which a majority of worker bees in a colony disappear, leaving behind a queen, plenty of food, and a few nurse bees.

According to the study, published in the journal Science, an increasing number of honey bee colonies have seen the dwindling of their adult bees with beekeepers in the US alone losing nearly 40 per cent of their colonies last winter.

It said without honey bees, dozens of crops, from almonds to berries to broccoli, would either vanish, or produce significantly less food across the world.

The new bacteria engineered by researchers, including those from the University of Texas at Austin in the US, live in the guts of honey bees, and act as biological factories, pumping out medicines protecting the bees against two major causes of colony collapse -- Varroa mites, and deformed wing virus.

According to the scientists, this method of protecting the bees with engineered gut bacteria may one day scale up for agricultural use since the bacteria are easy to grow, with a straightforward method of inoculating the bees with them.

"It has direct implications for bee health," said Nancy Moran, study co-author from the University of Texas at Austin.

"This is the first time anyone has improved the health of bees by genetically engineering their microbiome," added Sean Leonard, a graduate student and first author of the study.

The study noted that the mites and the virus often come together.

As the mites feed on bees, they can spread the virus, while also weakening the bees and making them more vulnerable to infectious agents in the environment, the scientists explained.

To address both the problems, the researchers engineered one strain of bacteria to target the virus, and another for the mites.

Compared with control bees, the bees treated with the strain of bacteria targeting the virus were about 36 per cent more likely to survive to day 10.

Varroa mites feeding on another set of bees treated with the mite-targeting strain of bacteria were about 70 per cent more likely to die by day 10 than mites feeding on control bees.

The scientists added that the studies were conducted under strict bio-containment protocols used with genetic engineering.

They added that even without such protocols, the risk of the engineered bacteria escaping into the wild and infecting other insects -- and thereby conferring some anti-pest or anti-pathogen superpowers -- is very low.

According to the researchers, the type of engineered bacteria are highly specialised to live in the bee gut, and can't survive for long outside of it.

However, they added that further research will be needed to determine the effectiveness and safety of the treatments in agricultural settings.