Genetic engineering as protector of the harvest
Building up to a success story
In order to be prepared for PRSV infections in Puna, Cornell University (research group led by Dennis Gonsalves) and the University of Hawaii( research group led by Richard Manshardt) initiated a research program in 1979. Within this program they wanted to explore the possibilities of cross protection.3 Cross protection is a method involving the deliberate infection of plants with weak viruses. These viruses do not usually cause any disease but do activate the plant’s immune system whereby later infection by viruses related to the mild virus can be better dealt with. Cross protection against PRSV showed limited success.3 This method relies on the existence of a mild virus that can effectively offer protection against PRSV. It was possible to create a low level of resistance in some papayavarieties, primarily resulting in a delayed progression of the disease, but in many cases this resistance was too weak or the mild virus still caused certain disease symptoms. Additionally, this method requires extra work from the farmer and very close monitoring, making it too impractical to be viable