The recent midterm elections have gotten a lot of people talking. The balance of power on Capitol Hill changed. And marijuana aficionados in Oregon, Washington, D.C. and Alaska are just high on life right now because cannabis has been legalized there. But there’s another kind of green that you might not have heard much about through all of the talks about fiscal policy and cannabis: papaya plants.
Voters in Hawaii just approved a bill that bans the planting of genetically engineered seeds on the islands of Maui and Molokai until the counties conduct a thorough review of the potential health and environmental effects. What does this have to do with viruses, you might ask? Well, one of the reasons that GMO papaya exists in Hawaii at all is because of a deadly virus that decimated Hawaii’s papaya in the 1990’s. Although Hawaii is a relatively small part of the global papaya industry (0.1% of papayas produced globally), this represented millions of dollars of economic loss (Hawaiian papaya exports generated $23 million USD in 2012, http://www.vib.be/en/about-vib/plant-biotech-news/Documents/Virus%20resistant%20papaya%20in%20Hawaii.pdf). Papaya ringspot virus (PRSV) is a naked rod-shaped virus of the family Potyviridae, a large family of plant viruses that includes almost 1/3 of all known plant viruses. It is transmitted between plants through pruning multiple plants with the same pruners, and through certain species of aphids (kind of like sharing needles or contaminated blood products). Like tobacco mosaic virus (TMV), PRSV can cause wilting of leaves and lead to deformed leaves and fruits. The development of GMO papaya in Hawaii was initially heralded as a good thing for the state’s papaya, but now people don’t seem as open to GMO papaya.
Is this a plant analogue to anti-vaxxers who aren’t scared of measles now that cultural memory of diseases like measles is fading away? Or should we be seriously concerned about the health and environmental effects of GMO plants, especially for the historically vulnerable insular ecosystems of the Hawaii Islands? There is definitely a risk of cross pollination with wild plants, but nobody can seem to agree on whether GMO fruits are safe to eat.
In this class, we have focused on viruses that affect humans, but viruses that affect our food have serious effects on human wellbeing.
Riechmann JL, Lain S, Garcia JA (1992) Highlights and prospects of potyvirus molecularbiology. J Gen Virol 73:1–16.