Anti-GMO Activist Roseanne Barr: GMOs caused Papaya Ringspot Virus

Roseanne Barr is an American actress perhaps most well-known for her role in the TV-show Roseanne (1988-1997). The show tackled many important issues such as obesity, race, class, feminism, domestic violence and LGBT rights. Since then, Barr has run for President for the Peace and Freedom Party in 2012 and become a prominent social activist.

However, dark clouds started appearing on the horizon. In July of 2012, Barr asserted that people who eat at the fast food restaurant Chick-fil-A chain deserves to get cancer (see the tweet conversation below that tweet). This was in response to public statements made by Dan T. Cathy disapproving of same-sex marriage. While same-sex marriage is an important social issue to defend and opponents will find themselves on the wrong side of history, it is both ethically and scientifically dubious to say that people who get cancer deserves it. It is also ironic that Barr claims to be against racism and classism when things like poverty and discrimination being “obstacles to receiving health care services related to cancer prevention, early detection, and high-quality treatment” (American Cancer Society, 2013, p. 43) for ethnic minorities. Later the same year, she came under fire again for making transphobic remarks, presumably because of Green Party presidential candidate Jill Stein’s support for trans rights (Barr lost the Green Party nomination to Stein). Some commentators pointed out the hypocrisy of claiming to take class issues seriously at the same time as discriminating against trans women who cannot afford gender reassignment surgery.

Recently, I replied to a tweet by an anti-GMO activist calling for the ban on genetically modified foods on Hawaii by pointing out that biotechnology saved the Hawaiian papaya industry in the 1990s from almost complete collapse by engineering the papaya to be resistant to the papaya ringspot virus (PRSV). The anti-GMO activist was apparently not aware of this, so she retweeted me @TheRealRoseanne. Barr, who had apparently become an anti-GMO activist herself, tweeted this (webcite) in reply:

Barr thinks GMOs created PRSV

There is one big problem with that claim: the papaya ringspot virus was first reported on the Hawaiian island of Oahu in 1945. Transgenic papaya was not released in Hawaii until 1998.

In fact, phylogenetic analysis puts the origin of the PRSV version that infects papayas at 500 years ago (concurrent with the arrival of the papaya in the region including Indian and China). Unless multinational corporations traveled 500 years back in time, there is no way that GMOs or GM corporations caused or created PRSV.

It is very important to understand how badly the PRSV virus damaged the Hawaii papaya industry. In 1956, Oahu grew 243 ha papaya and after just twelve years, it had declined to less 16 ha. The papaya production largely moved to the Puna district, where it grew around 25000 ton papaya per year (~95% of the entire papaya production on Hawaii). PRSV reached Puna in 1992 and within just three years, it managed to almost completely shut down commercial production of papaya in the district.

Scientists inserted a single gene into the papaya to make it resistant to PRSV and produced two major lines of PRSV-resistant papaya (called “SunUp” and “Rainbow”). This gene produces an mRNA that is complementary to the mRNA of the virus coat protein. These two mRNAs anneal to each other and the resulting complex degraded by the plant using its natural defense system. This has two consequences: (1) the virus cannot produce coat protein and therefore does not spread from an infected cell and (2) the mRNA degradation enables the plant to perform a targeted destruction of viral coat mRNA.

Thus, researches saved the papaya on Hawaiian. This solution was so successful that in 2010, 80% of all papaya produced in Hawaii was genetically modified (Ronald and McWilliams, 2010). For additional information about the historical, biological and societal aspects of PRSV, please see papers by Tripathi et al. (2008), Bateson et al. (2002), Ferreira et al. (2002), Gonsalves (1998), Fermin et. al (2004) and Tripathi et. al (2007).

Presumably, Barr made a knee-jerk reaction against everything related to GMOs because she dislikes big corporations (she has previously referred to Monsanto as “Monsatan”). However, that has nothing to do with the GM technology itself or the well-tested products made from it. Those are two completely separate issues just like disliking Starbucks is not in itself an argument against coffee.


Roseanne Barr is dangerously misguided with respect to GM technology and products and her disdain for large corporations bleeds over into an irrational hatred of GMOs.

As a public intellectual, Barr has an intellectual responsibility and should not abuse her own fame to spread pseudoscience about GMOs.

References and further reading

Ronald, P. C. & McWilliams, J. E. (2010). Genetically Engineered Distortions. New York Times. Accessed: 2013-07-06 (webcite).

American Cancer Society. (2013). Cancer Facts & Figures 2013. Atlanta: American Cancer Society.

Bateson, Marion F., Lines, Rosemarie E., Revill, Peter, Chaleeprom, Worawan, Ha, Cuong V., Gibbs, Adrian J., & Dale, James L. (2002). On the evolution and molecular epidemiology of the potyvirus Papaya ringspot virus. Journal of General Virology, 83(10), 2575-2585.

Tripathi, Savarni, Suzuki, Jon Y., Ferreira, Stephen A., & Gonsalves, Dennis. (2008). Papaya ringspot virus-P: characteristics, pathogenicity, sequence variability and control. Molecular Plant Pathology, 9(3), 269-280.

Ferreira, S. A., Pitz, K. Y., Manshardt, R., Zee, F., Fitch, M., & Gonsalves, D. (2002). Virus Coat Protein Transgenic Papaya Provides Practical Control of Papaya ringspot virus in Hawaii. Plant Disease, 86(2), 101-105.

Gonsalves, Dennis. (1998). Control of Papaya Ringspot Virus in Papaya: A Case Study. Annual Review of Phytopathology, 36(1), 415-437.

Fermín, Gustavo, Tennant, Paula, Gonsalves, Carol, Lee, David, & Gonsalves, Dennis. (2004). Comparative Development and Impact of Transgenic Papayas in Hawaii, Jamaica, and Venezuela. In L. Peña (Ed.), Transgenic Plants: Methods and Protocols (Vol. 286, pp. 399-430): Humana Press.

Tripathi, Savarni, Suzuki, Jon, & Gonsalves, Dennis. (2007). Development of Genetically Engineered Resistant Papaya for papaya ringspot virus in a Timely Manner. In P. Ronald (Ed.), Plant-Pathogen Interactions (Vol. 354, pp. 197-240): Humana Press.

Emil Karlsson

Debunker of pseudoscience.

14 thoughts on “Anti-GMO Activist Roseanne Barr: GMOs caused Papaya Ringspot Virus

  • July 7, 2013 at 01:03

    Actually, she’s got an organic farm now–so she’s not just commenting without a reason to influence the perception of organics. She’s part of the organic industry.

  • Pingback: Anti-GMO Activist Roseanne Barr Goes Off the Deep End | Debunking Denialism

  • July 9, 2013 at 18:38

    Just saw a tweet from her asking for followers to help debunk this debunking. Kinda hard to do when the facts are pretty clear. Hopefully they will get some good info out of this and help them decipher the mass wave of misinformation that is washing over Hawaii right now in regards to GM. Thanks for the great post.

    • July 9, 2013 at 23:14

      Thank you for your kind comment!

      Yeah, one such tweet can be found here:

      I find it interesting that many people do not realize that someone can do a webcite cache on their tweets, so even if they delete them in the future, they are still online. For future reference, I have webcited all of Barr’s tweets directed at me or my blog (mostly so I can post stable links to tweets that I post screenshots of so others can confirm that they are legit).

      In tweeting above, Barr did two mistakes: (1) she comes off as being unreasonable and frantic as she posted in ALL CAPS again, accused me of being a Monsanto shill and called me a “science debunker” but also (2) she tweeted a link to my blog, giving it exposure among her 200k followers (big thanks!).

      As I’m writing this, I noticed that Barr also tweeted the following:

      Here she states that she will admit that she is wrong after a while if she cannot find a study unpaid by Monsanto (the studies that I linked were not paid for by Monsanto but by a USDA grant program).

      If she does admit that she was wrong, then that is very intellectually admirable since she appeared to be very deep in the anti-GMO camp and it would probably deserve a follow-up post with praise from me (hopefully I will remember to regularly check her tweets during the following weeks so that I do not miss it should it occur).

    • July 12, 2013 at 01:06

      SAS, Shill Accusation Syndrome, strikes even the rich and famous, such as Roseanne Barr.

      Shill Accusation Syndrome. It strikes those who just can’t believe other people can independently come to a different conclusion than their own. Help stamp out SAS in our lifetime.

    • July 12, 2013 at 11:49

      I appreciate the sentiment, but it is worth being careful with labeling people with ignorant beliefs with a (pretense) psychiatric diagnosis. Having a mental condition is a serious situation and it is beneficial to not associate it with ignorance or idiocy.

  • July 10, 2013 at 12:39

    Roseanne Barr is still working tiredless to come up with evidence countering my refutation of her claims. Here is what she has come up with so far:

    The link in question goes to an overview of transgenic papaya and how it helped save the Hawaii papaya industry from collapse. It does not support her claims whatsoever (ironically, that overview uses several of the same sources I did and does not come to a different conclusion).

    This is because she thinks that the cross-protection of conventional papaya (loosely analogous to vaccination) that was developed in the late 70s is the same as the development of the transgenic papaya that was released in 1998. These are of course two separate approaches and it is worth noting that PRSV was reported on Hawaii over 30 years before cross-protection was attempted (and of course existed in China several hundreds years earlier than that).

    Barr is digging herself deeper and deeper. Her best move is to just retract her initial claim before she loses additional credibility.

    • July 13, 2013 at 02:56

      As a Hawai’i Island resident, I’m aware of Ms Barr’s mean streak, along with her addiction to twit tweets. The lady is plainly unstable.

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  • July 21, 2013 at 02:14

    To keep in the spirit of debunking poorly thoughtt-out ideas, how about taking a closer look at the gmo posterchild, the Sunup, Rainbow, and Sunred papayas?

    Have you found any sources about safety testing done on humans? Are you aware of the exemption for a known allergen that GMO papayas have receieved? Are you aware of the three antibiotic marker genes in these GMO papayas? What about the recently found (by scientists) “hidden viral gene segment” that the developers were not aware of and continue to deny? Do you know why GMO papayas need lots of spraying? Because it as actually more prone to Black Spot Virus.

    You may want to look further than the ring of GMO papaya creators and supporters, their sources, and their comments written above. Perhaps its time to debunk the slick image GMO papaya maintains despite the fact that papaya growers can barely sell their GMO papayas while organic papayas fetch top dollar. The papaya is the GMO poster child indeed–its just too bad that the true story is kept under wraps by intimidation by good ole’ boy network and local media that refuses to publish any thing that might tarnish the papayas image. For real.

    • July 21, 2013 at 14:15

      None of your assertions is supported by the science. They are either outright false or selective fear-mongering. What is curious is that your false claims could easily be debunked by spending just a few minutes on a search engine. How embarrassing for you.

      Safety testing

      Yes, safety testing has been carried on on genetically modified papaya, just like any genetically modified food item. I suggest that you read

      Fuchs, Marc, & Gonsalves, Dennis. (2007). Safety of Virus-Resistant Transgenic Plants Two Decades After Their Introduction: Lessons from Realistic Field Risk Assessment Studies. Annual Review of Phytopathology, 45(1), 173-202.

      From the paper:

      However, safety issues are not specific to transgenic plants expressing viral genes. They also apply to conventional plants that are subjected to virus infection. It is the engineered trait, e.g., virus resistance, and the transgene, e.g., a virus-derived gene construct, that are the source of potential concern, not the methodology used to develop a virus-resistant plant. Therefore, it is critical to determine a baseline level of occurrence against which the impact of transgenic plants is compared

      No allergens in transgenic papaya

      They also point out that:

      Numerous observations suggest that a viral protein in transgenic plants does not pose a threat to allergenic safety. Most notable is that virus-infected crops have been consumed since plants have been food with no apparent ill effects known to be due to virus components.


      Similarly, no ill effect has been reported from the consumption of papaya fruits harvested from thousands of trees that were deliberately inoculated with a mild strain of PRSV. Also, to the best of our knowledge, there is no scientific report documenting any plant viral CP as allergen.

      As for “know allergen”, the situation is not what you claim it is. The paper explains:

      None of the virus-derived products expressed by these transgenic crops can be considered a potential allergen if one uses the suggested criteria of minimum sequence relatedness (35%) and a continuous stretch of eight identical amino acids to known allergens (49). However, using six contiguous identical amino acids as criterion, the CP of PRSV strain HA 5-1, which is expressed in transgenic SunUp and Rainbow papaya, matches with the putative ABA-1 amino acid allergen determinants of roundworms. Nevertheless, a 2002 report showed that the ABA-1 protein is not an allergen by itself, indicating that a stretch of six identical amino acids was not a valid approach for judging potential allergens. Other criteria for protein allergenicity are their stability in simulated gastric juices and stability to heat. Studies on transgenic papaya showed that the CP of PRSV strain HA 5-1 is digested in simulated gastric juices in less than 5 seconds after exposure, and much of the protein is degraded by heat (D. Gonsalves, unpublished observations). Altogether, allergenicity appears not to be a significant risk for PRSV-resistant transgenic papaya.

      In other words, this so called “know allergen” is not actually an allergen and is degraded very quickly in the stomach. You can read more about the dishonest tactics with “allergens” used by anti-GMO activists in an article on Academics Review.

      Antibiotic resistance markers

      Those pose no threat to human health or the environment, as those forms of antibiotic resistance are already well-spread in nature (and has been for decades) and we do not use those antibiotics for therapy anymore.

      A paper published in Lancet Infectious Diseases concludes that:

      We conclude that, although fragments of DNA large enough to contain an antibiotic-resistance gene may survive in the environment, the barriers to transfer, incorporation, and transmission are so substantial that any contribution to antibiotic resistance made by GM plants must be overwhelmed by the contribution made by antibiotic prescription in clinical practice.

      Hidden viral gene segment?

      The only information about this comes from Mercola, which means that we should be very skeptical as he has a long history of spreading quackery and nonsense about genetically modified foods.

      According to the European Food Safety Authority:

      1. Certain media reports have claimed a paper published in the academic journal GM Crops and Food: Biotechnology in Agriculture and the Food Chain had discovered a previously unknown viral gene in commercial GM crops that may present a hazard to human health. Is this claim true?

      No, the data published in the paper ‘Possible Consequences of the overlap between the CaMV 35S promoter regions in the plant transformation vectors used in the viral gene VI in transgenic plants’ do not represent a new discovery of a viral gene nor do they indicate safety concerns in previously evaluated GMOs.

      2. What is the viral gene discussed in the paper?

      The viral gene (Gene VI) belongs to a plant virus (Cauliflower Mosaic virus) that cannot infect animals or humans and therefore presents no threat to human or animal health. This virus naturally infects many plants with no recorded health effects.

      This was not a secret and the regulatory authorities have been aware of this since the creation of EFSA in 2002. No one is denying anything. Well, except anti-GMO activists who deny the science, of course.

      Spraying and black spot “virus”?

      First of all, the black spot disease is a fungal pathogen not a virus. Second, before resistance to PRSV, the papaya industry was almost completely wiped out. The PRSV killed papaya. The black spot disease does not cause any practically significant fruit damage.

      So in a choice between PRSV that wipes out the entire papaya industry and having to spray against black spot disease, the latter is clearly preferable. No contest.

      As it turns out, the black spot disease has been found at high levels both on conventional papaya cultivars and transgenic papaya cultivars, so it is a problem facing both transgenic and non-transgenic papaya (State of Hawaii: Department of Agriculture).

  • July 26, 2013 at 13:17

    You say that Roseanne Barr is, ”a public intellectual”, well, excuse me, Roseanne Barr is not ANY kind of intellectual, if she had any more than a passing resemblance to an intellectual, I, among many others, would have been sure to notice it. She is just another Jenny McCarthy, a fool, who has found a cause to propel her back into the limelight, it could be that she really believes all her babble, but I doubt it, I believe she doesn’t actually care whether she is right or wrong, and that makes her even more dangerous than someone who is just misinformed.

    • July 26, 2013 at 13:22

      In a comment on the next part in this series, I acknowledged that “public figure” or “public commentator” had been a more appropriate and value-neutral term to use.

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