Scientists successfully created two virus resistant varieties of papaya. SunUp has reddish-flesh fruit and has 2 copies of the coat protein (cp) gene. Rainbow is a hybrid of SunUp and a popular non-transgenic variety. It has a yellow-flesh fruit, and only one copy of the coat protein (cp) gene. In what turned out to be serendipitous timing, PRSV resistant transgenic papaya was being field tested just as the Puna region papaya plantations were being decimated by PRSV in the early 1990s. Despite the positive results in the early field trials of resistant papaya, some farmers initially were pessimistic about the potential of the transgenic fruit. This is understandable, of course, given that their livelihoods were at stake. > Step 3: Getting Approval to Grow "What we had done through the field trial would only be academic unless the papaya got through the red zone of translational biotechnology… getting the papaya deregulated and commercialized." ~ Dennis Gonsalves
Although the experiments indicated that the transgenic papaya were resistant to PRSV, the plants could not be used commercially until they were approved by regulatory agencies. The virus protein coat gene inserted into the papaya genome is considered a pesticide because it acts against the virus—a papaya pest. So the Environmental Protection Agency (EPA) and US Department of Agriculture (USDA) had to approve the transgenic organism's environmental and agricultural safety. The Food and Drug Administration (FDA) considers food safety; it also granted approval and deemed the transgenic papaya safe for consumption since PRSV breaks down quickly in the human stomach
. All three agencies provided approval. After getting the licenses to commercialize the transgenic papaya, in 1998 the seeds for the transgenic papayas were distributed free to growers.
Once the regulatory hurdles were cleared, farmers in Puna quickly accepted and started growing the transgenic papaya. They were delighted to have virus resistant plants that produced good yields. As of 2014, transgenic papaya made up 85% of the Hawaiian papaya crop. US consumers bought the transgenic papaya; Hawaiian transgenic papayas are also sold in Canada, Hong Kong and Japan.