Community Research and Development Information Service - CORDIS

For oysters, resistance to death is in the genes

The herpes virus is killing Europe's most valuable oyster in droves. An EU research group is using resistant genes in these oysters to help populations of this commodity to bounce back.
For oysters, resistance to death is in the genes
The deaths of a great number of Pacific oysters, the most lucrative oyster market in Europe, have been linked with herpes virus. Mostly killing juvenile oysters, immunisation to the virus is not possible as oysters lack an adaptive immune response.

In the EU-funded study HERPISH (Herpes virus in Irish oysters and identification of resistant stocks), researchers aimed to sequence RNA from Irish populations of cultured oysters to find any potential genetic resistance to the herpes virus.

To find these traits, HERPISH conducted field trials and surveys to fish out oysters that were resistant to the herpes virus. In the trials, researchers compared the health of oysters that had been previously infected with the virus to other oysters that had not been infected.

Next, researchers placed oyster populations in areas known to have the virus as well as places where it had not been detected. The surviving oysters from the field trials were then infected with the herpes virus in a laboratory to test their resistance to it.

HERPISH bred the surviving oysters in the lab and exposed the offspring to the virus to test their resistance to the virus as well. Finally, researchers sequenced the oysters' RNA to find the genes responsible for resistance.

Those oysters that were never infected with the virus remained so, even when conditions favoured the disease. A lot more oysters died in some infected sites than in others as a result of resistance to herpes virus.

Importantly, HERPISH found several defence genes in virus-resistant oysters, which can be used in future breeding programmes to limit Pacific oyster deaths.

Related information


Oysters, herpes virus, Pacific oysters, HERPISH, genetic resistance
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