Papaya and the Use of Genetic Viral Protection

    The Papaya plant may seem exotic to most mainlanders, but it is actually a very important fruit grown in the islands of Hawaii. While a large part of agricultural life on the island, Hawaiians faced a growing threat to their livelihood in the form of a devastating virus known as Papaya Ringspot Virus. Gmocompass describes the effects of prv in its article “Papayas” as stunting to the trees, causing them to take on an unhealthy, naked look as they are shorter than regular papaya trees and have less leaves covering their tops (2016).

       The process undertaken to protect the papaya trees is highly reminiscent of the way immunities are developed in humans through vaccinations. The article describes how certain types of viral proteins are inserted into the genes of the papayas which causes the papaya to fight back and develop a more powerful immune response to the viruses of that type. This results in the papaya plants getting total protection from the papaya ringspot virus, as they are better equipped to fight off the affliction with their genes. This development has allowed cultivators in Hawaii to plant the gm papayas in widespread locations and have them thrive even while prv is running rampant around their crops. There are actually pictures of natural and modified papaya trees planted parallel to each other, showing how the prv in the area is devastating the natural trees, while the modified papaya trees are as strong and healthy as if there were no viruses around whatsoever.

     The modified papayas first appeared in 1999 but have over time become the dominant form of papaya grown in Hawaii. The total cultivated space covers 3/4ths the entire papaya crop area with little sign of the adoption rates changing. As far as world acceptance, there is growing research and development into the process used to combat the papaya ringspot virus by other Asian countries who want to alter the crop themselves to combat the viral strains it would face being grown in their local areas. Both the United States and Canada have approved the consumption of GM papaya in their territories and serve as the largest customers of the crop.

      Meanwhile, the European Union has not approved the consumption or import of gm papaya, and because there have been no proposals to the EU for approval, it may be a while before their status gets reviewed. For now, it is illegal to import and market the modified papayas in any of the member states of the EU.

     While many genetic modifications of plants tend to increase resistance to herbicide and pesticide use, and maintain the aesthetic appeal of the crop by eliminating brown spots from bruising and cutting, the modification of papayas presents a unique appeal of modification that cannot as of yet be managed by anything else. There are no pills or medicines that can be given to plants that are already sick, and so genetic modifications of the plant so as to provide it a defense against debilitating pathogens have proved to be one of the best ways to preserve yields and growth of successful fields. However, for many people the dangers of genetic modification still outweighs the benefits of it, and even the rarity of overcoming the problem through other means still doesn’t provide enough of a justification to promote the acceptance and use of gm plants. For the papaya there are hopeful signs with the widespread adoption already seen in North America, but the approval of the EU on using the crop will be integral to seeing a more widespread acceptance of what the technology offers.

Source: Gmocompass. (2016). Papayas. Gmo-compass

Examining Inborn Defenses against Pests in Leptra Corn

     One of the most prevalent traits of genetically modified plants is their ability to resist insects that would normally consume and destroy the plant. One recent addition to the family of gmo plants created to protect itself from insects is a hybrid plant created by DuPont Pioneer and is known as Optimum Leptra. The website states that the modification is to the corn plant and is designed to reduce the ear feeding of lepidopteran pests which delivers cleaner ears with less kernel damage and that it eliminates the major risk of development of molds and mycotoxins in harvested grain (“Optimum Leptra Hybrids”).

      An article by Clarin Rural, covering news in the Latin American regions, talked about how the corn will soon be introduced in Argentina after having the Ministry of Agro Industry approve the marketing of the plant (“Resistant corn comes with four transgenic events”). The article gives more details on the function of the modifications, stating that two of the events protect against stem borer and isoca Tang, a double event for protection against fall armyworm and glufosinate ammonium with a room for glyphosate. The corn has already been made available in Brazil and hopes carry to better yields with it in Argentina.

     In the United States the protections on the crop protect it from different pests. In the article “DuPont Pioneer releases Optimum Leptra Hybrid” on AGProfessional, in the United States the insects repelled by the modifications of the corn include European and Southwestern corn borers, the corn earworm, and black and western bean cutworms. In the article, penned by the DuPont Pioneer Company, they cite figures of 98% reduction in ear feeding damage using their crops. The plants are also resistant to herbicides, protecting them from more types of poison control.

     Some of the traits found in the corn have long been used in other genetically modified plants produced by DuPont, and have long known mechanisms for working. For example, Herculex I, a trait available in Leptra to kill bugs functions by being ingested by larva who feed on the modified plant. The protein binds to receptors in the gut of the larva and causing a series of reactions which ultimately lead to the death of the larva (“Herculex FAQ”).

      As with any genetically modified food, of course, there are questions about the effects these different traits may have on the ecology around it. Modified plants that have natural pesticides and that are resistant to herbicides and pesticides have been shown to cause resistant strains of weeds and pest insects to survive and reproduce, causing a drop in the effectiveness of the traits modified in the plants. The article “How pesticides develop” by Michigan State University explained that worldwide more than 500 species of pests have developed a resistance to pesticides due to the growth of resistance among their populations.

      Even so, the Clarin Rural article goes on to state that the importance of the Leptra crop is that, since it has so many different resistance traits it makes it easier to rotate the amount of herbicides and pesticides needed for cultivating the crop. In addition, the natural pest defenses the corn has should also reduce the amount of poison needed as it is targets the greatest pests that threaten the growth of corn plants in the regions the crop is planted in. All of these different additions may prove to be fundamental in helping feed a world that is highly defendant on its corn plants on production, if they can get past the stigma of genetic modification and scientific uncertainty.

Sources:

Clarin. (2016). Argentina approves new GMO corn with four traits for insect, pesticide resistance. Genetic Literacy Poroject. 

Dow AgroSciences. (2016). Herculex I FAQ. DowAgro. 

DuPont Pioneer. (2013). DuPont Pioneer releases Optimum Leptra hybrid. AGProfessional. 

Gut, L., Schilder, A., Isaacs, R., & McManus, P. (2016). How Pesticide Resistance Develops. Michigan State University. 

Pioneer. (2016). Optimum Leptra Hybrids. DuPont Pioneer.