What are genetically modified apples? It's GMO awareness month, which means the public cry against Genetically Modified Organisms (also called Genetically Engineered Organisms, abbreviated as GEOs) is in full tilt. It's therefore an appropriate time to let Canadians know that their beloved apples are also under threat of becoming unnaturally manipulated in the lab. In this 6 part blog series, I detail the reasons for and against the proposed new breed of this delicious pomaceous fruit.
In Part 1 of this blog series, I described the background for why a fruit growing company called Okanagan Specialty Fruits (OSF) based in Summerland, British Columbia, applied to Health Canada and the Canadian Food Inspection Agency for approval of a genetically modified (GM) apple. In Part 2, I will give a brief background of what it means to genetically engineer an apple and I debunk the OSF's claim that GM apples safer than other GMOs.
Introducing the Genetically Modified Apple ~ It's Nonbrowning
The OSF genetically modified nonbrowning fruit, called the ArcticTM apple, has been developed primarily for use in the food industry. It’s intended to prevent browning of pre-cut apples for fast food, food processing, and food service companies. However, the apples will eventually also be sold to the public for personal consumption. OSF has currently produced GM Golden Delicious and Granny Smith varieties and plans to follow with GM Fuji and Gala cultivars.
The technology used to produce GM ArcticTM apples has been under development since 1997. Australian scientists refined the procedure of silencing genes that code for PPOs in potatoes. OSF then licensed the gene silencing technology and produced a nonbrowning apple variety. Test plots were planted in 2003 and 2005 while research and development of the apple continued.
How to Genetically Modify an Apple that Doesn't Brown
If nonbrowning apples could potentially save the apple industry from financial losses and product spoilage, then why the public outcry about the ArcticTM apple? The issue is actually bigger than the apple itself. Even though GM technology is almost four decades old (in 1973 the bacteria E. coli became the first organism to be genetically engineered), the ecological and biological safety of GM organisms (GMOs) remains contentious.
Genetically engineered crops were first released in 1986 and subsequently commercialized in 1998. They currently grow over an area covering more than 81 million ha across 17 countries with approximately 99% of that area existing in the United States, Argentina, Canada, and China. Despite this widespread cultivation of GM crops, relatively little is understood of the potential long-term consequences GMOs can have to the health and wellbeing of humans, wildlife, and ecosystems.
In defence of the GM ArcticTM apple, OSF claims that their fruit product is created using GM technology that’s unique and seemingly more innocuous than traditional GMOs. They claim that ArcticTM apples aren’t transgenic—that is, the apples don’t contain embedded foreign genes from another organism. Instead, the genetically engineered parent apple tree contains only apple modified genes—the silenced PPO apple gene sequence, called GEN-03, is inserted into the DNA of the apple shoot, which is then grafted onto the parent crop tree to produce nonbrowning apples.
This form of genetic engineering has been termed cisgenic or intragenic (that is, genes from the same species are used to produce the GMO), in contrast with the traditional transgenic technique (that is, genes from different species are mixed into a single GMO). Biotechnology companies often exploit this distinction to misleadingly give the impression that cisgenic organisms are safer than transgenics because it’s claimed that cisgenic GMOs lack DNA from a foreign species. Although cisgenics may seem superficially safer, the truth is that the technique still involves (and necessitates) the use of bacterial and/or viral genomic vectors to insert the modified gene into the host plant.
In the case of the ArcticTM apple, the promoter and terminator sequences (the parts of the gene that facilitate gene transcription and that signal the end of the gene sequence or operon, respectively) are derived from the cauliflower mosaic virus (CaMV) and the bacterial gene coding for nopaline synthase (nos), respectively. The Gram-negative pathogenic soil bacteria that causes crown gall (tumour) formation in many plant species, Rhizobium radiobacter (syn. Agrobacterium tumefaciens), operates as the vector for inserting the engineered apple gene into the parent apple tree. The nos gene is located on the tumor-inducing (Ti) plasmid of R. radiobacter and it helps researchers identify which cultured apple cells have been infected with the silenced PPO gene.
Therefore, cisgenic organisms can’t be considered “natural” or even definitively innocuous because they contain genes from more than a single species and they therefore pose the same threats as transgenic plants.
I'll explore the distinctions between transgenic and cisgenic organisms in future blogs. In Part 3 of this blog series on GM apples, I discuss the potential ecological dangers of GMOs.
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You can download a .pdf of the article in its entirety, including references, at the bottom of this page.