Bidirectional Transfer of RNAi between Honey Bee and Varroa destructor: Varroa Gene Silencing Reduces Varroa Population
We previously reported that honey bees fed on double-stranded RNA (dsRNA) with a sequence homologous to that of the Israeli acute paralysis virus are protected from the viral disease. Here we show that dsRNA ingested by bees is transferred to the Varroa mite and from mite on to a parasitized bee. This cross-species, reciprocal exchange of dsRNA between bee and Varroa engendered targeted gene silencing in the latter, and resulted in an over 60% decrease in the mite population. http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003035
"Funding: This work was supported in part by in-house funds of the B. Triwaks Bee Research Center, by Beeologics LLC, by USAID-MERC (grant no. TAMOU-08-
M29-076) and by the Clore Israel Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the
manuscript.
Competing Interests: Patent pending: The authors assigned their rights to Yissum research development company of the Hebrew University of Jerusalem LTD,
which together with Beeologics LLC submitted a patent application entitled ‘‘Compositions for controlling Varroa mites in bees’’ (Serial No. 61/251,339) on
October 14, 2009. IS was the Chief Scientist of Beeologics. EM was an employee and consultant of Beeologics. This does not alter our adherence to all PLoS
Pathogens policies on sharing data and materials."
the colonies were started with approx. 250 bees and a queen, which only built up to about a thousand bees by the end of the experiment. (mini hives)
60% reduction meant the difference of a 4% average infestation rate in the nontreated group, as compared to a 1.5% infestation rate in the better of the two treated groups.
3% infestation is used by some (see beeinformed.org) as a threshold beyond which varoasis is more likely.
my guess is that field studies will be forthcoming.
I sat in on his talk a few years back, have they gotten the treatment down to an affordable commercial dose? Deformed Wing Virus was also brought up. This work is huge. If proven to become commercially successful, it will help bring back certainty in measuring varroa mite populations in regards to hive injury and allow more accurate monitoring thresholds. Now we are all over the map and dont know what to expect.
I'm a dummy - so please pardon the question, I've just seen thing like this in other "products".
If this modified version of the dsRNA with Varroa Gene Silencing gets into the honeybee and is spread by breeding bees having this modification do the offspring contain the modified dsRNA? And what are the implications if this modification is patented?
the gene is fed to the bee and gets into the bees system, the mite sucks the gene in when it is drinking the bee's hemolymph, it gets in the mites dna, the mother mite passes it on to her progeny, it results a birth defect that kills baby mites.
i'm not sure how much of it stays in the bee and/or affects bee genetics.
this is a different use of transcript rna than was used for giving the bees resistance to viruses.
the real unkown is what effect or not does introducing genetic traits to a parasite of the bee have on the bee? and whether or not there may be effects beyond the bee and the mites?
yep, that work involved introducing genes in the bees food that ended up in the bee genome, and resulted in an artificially aquired immuntity to certain viruses.
this newer work is introducing genes targeting the mite genome that result in mortality to the mite.
(after a more careful second reading of the new paper, i learned that the mites can also get the gene by simply coming in contact with it in the hive. also, once in the mites, the genes can be transferred to the bees by the mites).
on the question of what effect if any might the introduced gene have on the bee and beyond, the authors write:
"To prevent off-target human or bee gene silencing, these sequences did not correspond to any A. mellifera or human genes".
It's not really a gene. The dsRNA silences targetted sequences and does not self replicate. It essentially silences the selected mite genes it's sequence is based off of. To take it one step further, you could genetically modify bees to naturally express the sequences but a topical would be much easier to approve and avoid all the GMO debates. Another option could have a plant express it and supply the pollen/nectar to the bees. Still, I'd like to see better efficacy before I would try it.
Depends on the language of the patent, currently no bees have the gene as there isn't one. The dsRNA is put together synthetically but can be expensive depending on the size of the oligos. To put the gene in the bee would be very expensive and then the deregulation costs and arguments about honey made by a GMO organism will ensue. A topical treatment of the oligos avoids those discussions for now. If it came down to modifying the bee, I would imagine the patent would not allow knowingly propagating the line unless you had a license to do so, just like all patent protected species (trees/plants/etc...)
I'm just glad I have an isolated bee population with virtually no varroa mites for the last year, and no commercial beeks nearby, and no monsanto corn or soybeans nearby. Cattle don't carry gmo genes yet...
Sugar shake and pulling drone brood. SBB's when I have time to clean the sticky board. But the inspector and I went through 5 hives and pulled every drone brood larva and found ONE mite. I think one turned up in the sugar shake. My population is isolated, and I had an accidental brood break of about 3 weeks on the cutout hive before my nucs came, had about 5 weeks brood break on the hot hive after I killed the queen and before they requeened. My nucs were vsh bees. They've done well, bought 2, have basically 4 hives of them now. (one is at my neighbor's)
Flower, it's a topical treatment or in this case, it was fed to the bees, has nothing to do with genetic modification of the bee. There is no gene expression either, the rna does not replicate.
Yes this is real good...Monsanto applying for a patent...We'll see how much bees cost when your queen mates with a drone with this newly acquired Monsanto DNA and your making splits and nucs for sale. Hope you have deep pockets. For all those hoping for a godsend this is not it. You will have to pay Monsanto to raise bees and if not pay heavy fines..can you control your drone yard? Good luck!
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