While all the recent biotech limelight has been on gene editing, especially CRISPR, another older GM crop 'improvement' technique has continued to creep quietly up on us.
RNA interference, 'RNAi', which artificially alters gene expression, is still with us .Note. RNA interference is also known as double-stranded RNA, 'dsRNA'.
Although at the time no one actually knew why, the very first commercial, fresh GMO venture, the FlavrSavr tomato, ripened abnormally slowly due to RNA interference. GM papaya with RNAi-based viral resistance has been on some markets for a long time. Arctic apples which don't turn brown when sliced thanks to RNAi are working their way into US shops. GM-Free Scotland readers will be aware of Pandora's Potatoes with RNA interference to stop their bruises showing (even although the damage is still there), to stop them turning brown when fried (even although they taste like cardboard), to stop them producing the carcinogen, acrylamide (even although potatoes don't produce enough acrylamide to cause cancer), and to encourage potato growing in areas with a high risk of late blight (even if other crops could be better grown there) .
Many others are under development, but the blockbuster everyone's been waiting for is a commodity crop with its very own RNAi-based insecticide. This is a radical departure from what's gone before because the artificial RNAi in the GM plant will be designed to silence gene expression in another organism in its environment.
Very quietly, in 2017, the US Environmental Protection Agency (EPA) approved the first RNAi insecticide, 'DvSnf7'. It attracted very little attention from the press or environmental watchdogs because the EPA (not for the first time) didn't post its proposed decision in the Federal register and allowed only 15 days for public comment. The Center for Food Safety has pointed out that this totally unprecedented use of RNAi technology should have merited more public scrutiny.
Reassurances abound about how natural and safe DvSnf7 RNAi is. We're told, for example, that people are already eating stay-white fruit and veg with RNAi, and that the use of RNAi has already proven more environmentally friendly than the use of pesticides. RNAi, we're informed, is highly specific, silencing only one specific gene in only one specific species. The action of RNAi is based on a natural mechanism which plants and animals have always used to reduce the expression of their own genes. "In fact," as the directors of the Donald Danforth Plant Science Center (created with a significant donation of cash and land from Monsanto) tell us "as a naturally occurring biological process, RNAi was mediating plant metabolism, growth and pathogen defence long before humans began cultivating crops for their own benefit".
In short, RNAi is SAFE because it's ubiquitous in plants and there's a "history of safe use and consumption of naturally occurring and transgene-derived RNAi crops". The high species specificity minimises off-target effects. Moreover, because no GM protein is produced in the plants, they lack toxicity and allergenicity. Who could possibly be worried?
Accordingly, the EPA initially approved four 'SmartStax Pro' maize seed products with RNAi-insecticide to control the 'billion dollar bug', western corn rootworm .
SmartStax Pro is a belts-and-braces crop with five insecticide-producing 'Bt' genes besides DvSnf7. Scientists have already documented pests resistant to all these Bt proteins, and Monsanto (now Bayer) researchers have already generated rootworms resistant to DvSnf7 in order to study it. Pooling genetic resources with DowDuPont, SmartStax Pro will also have tolerance to glyphosate, 2,4-D and FOP herbicides.
The first wave of SmartStax Pro seed is expected in early 2020 as a 5% refuge-in-a-bag to prolong its commercial shelf-life.
If this sounds like another sprint on the same old pesticide treadmill, it is. And even the biotech industry is admitting it. The Center for Food Safety points out that by ditching the current "unhealthy practices in planting corn" and rotating a diversity of crops, farmers could get off that treadmill along with all the GM patent-controlled seeds that are keeping them there.
The safety of artificial RNAi in food was called into question in 2011 by a Chinese study which detected naturally-occurring RNA circulating in the bloodstream of people eating it. Biotech industry scientists with a vested interest failed to replicate the Chinese study. However, an American professor, who was aware of how difficult it is to reliably detect RNA in a living system, tried an experiment using a different approach to detecting RNAi: since RNAi is an active substance, she measured its effect in a living system. It emerged that, when laboratory mice bred to be prone to cancer were fed an RNAi construct known to suppress cell division, their tumour burden was reduced. However, with a little help from Monsanto, her inconvenient finding never saw the light of day .
A major concern about RNAi was highlighted by the creator of Pandora's potatoes: RNAi molecules break up the RNA they are interfering with to release a clusterbomb of RNA fragments. When this happens in their natural context, the debris is naturally cleared, but artificial RNAi is going to generate artificial RNA fragments, possibly in far larger quantities than naturally normal. These could be unpredictably active elsewhere in the genome. Other concerns were raised back in 2013 .
That same RNAi which will pass seamlessly into a pest when the corn is eaten by it will presumably pass seamlessly into you when you eat it. Let's hope that those assurances of specificity, under all physiological conditions and at all ages of the human consumer, are true because no one's checking (or if they are, the work's being suppressed).
The Donald Danforth directors repeat just about every assumption ever invented to 'prove' GM safe without the bother of conducting any science.
GM proponents never seem to tire of telling us that GM is really natural and must, therefore, be safe because we've always eaten it and that, we may not know it, but all we're worried about is GM protein.
Make sure you never tire of pointing out any artificial change forced into the DNA / RNA interactive, holistic complex at the basis of life processes will have extensive side-effects, and is unlikely to be compatible with a healthy plant, a healthy consumer of that plant, or a healthy ecosystem of which that plant is a part.
 RNA - A DOUBLE-STRANDED PROBLEM - July 2013
 IS PANDORA A MYTH? - December 2018
 THE BILLION DOLLAR BUG - May 2017
 dsRNA IN THEFIELD IS BAD NEWS - August 2013
- Sarah Zhang, The EPA Quietly Approved Monsanto's New Genetic-Engineering Technology, The Atlantic, 24.07.17
- Narender Nehra and Nigel Taylor, Improving Crops with RNAi, www.the-scientists.com, 1.06.15
- Aggie Mika, First RNAi Insecticide Approved, www.the-scientists.com, 27.06.17
- Emily Ungesbee4, Rootworm Trait Agreement, The Progressive Farmer, 17.05.18
- Caius Rommens, Pandora's Potatoes: The Worst GMOs, 2018, ISBN 9781986600835