Protective microflora
GM bacteria will protect bees from extinction
Sergey Vasiliev, Naked Science
Bees have been experiencing a slow genocide for the last decades. Their number has dropped significantly due to the syndrome of destruction of bee colonies, which is associated with the action of a number of negative factors, including the cultivation of agricultural monocultures, the use of pesticides from the class of neonicotinides.
But the main culprits of the epidemic are DWV viruses that cause deformity of the wings, as well as parasitic Varroa mites (Varroa destructor) that affect the fat body of bees and often spread viruses. However, Nancy Moran and her colleagues from the University of Texas at Austin seem to have found a method to make bees immune to the attacks of ticks and viruses.
To do this, they used bacteria, natural representatives of the intestinal microflora of bees, and modified their genome, turning microbes into defenders of their hosts, deadly to parasites. Scientists talk about their work in an article published in the journal Science (Leonard et al., Engineered symbionts activate honey bee immunity and limit pathogens).
The authors used the ability of RNA to suppress the work of certain genes. It is known that these molecules serve as intermediaries that transfer information from DNA to the ribosome, where a protein is synthesized on the basis of an RNA matrix. However, regulatory small RNAs can bind to a suitable matrix RNA, "deactivating" it and thereby inhibiting the expression of the corresponding gene. This process is called RNA interference, it is increasingly being used in science and medicine, and in 2006 the Nobel Prize was awarded for its study.
American geneticists decided to use interfering RNAs to suppress the work of key genes of viruses and mites that cause the destruction syndrome of bee colonies. To produce the right molecules, it is not necessary to interfere with the genome of the insects themselves. Unlike people with our diverse and complex diet, the nutrition of bees is quite limited, and the microflora of their intestines is not very diverse.
Human intestinal microflora can include hundreds and thousands of different types of bacteria, bees have only six or eight of them. This suggests that the new method will easily "take root" in populations around the world, although so far it has been tested only in the laboratory, and field tests are still to come.
So, the authors modified the symbiotic bacteria of bees Snodgrassella alvi, "teaching" them the mass production of RNA capable of interfering with the work of a number of key genes vital for DWV or varroa. GM bacteria were fed to 20 experimental insects before exposing them to contact with parasites.
And indeed: when meeting with such bees, the mortality among ticks jumped by 70 percent, and the mortality of bees themselves from DWV turned out to be 37 percent lower than that of insects that did not have GM microbes. Experiments have shown that such protection lasts at least 15 days – no longer monitoring was conducted. Moreover, the new bacteria were transmitted during feeding to the young, which gives hope that such protection can be maintained from generation to generation.
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