Gene editing crops to reintroduce benefits from wild relatives: an organic conundrum?

Reintroducing beneficial properties found in wild plants but missing from their domesticated cousins could strengthen crop varieties and reduce the need for chemical inputs, which would benefit organic farmers looking to increase yields. The authors of a review in the journal Trends in Plant Science suggest that despite organic agriculture’s rejection of genetic engineering, the most efficient way of reintroducing wild-type properties lost through domestication would be via new ‘precision breeding’ techniques, more commonly called gene editing. Exploring technical, social, ethical and legal questions, the authors argue that there is a place in organic agriculture for crops whose genome has been edited to make precise mutations, but where no foreign DNA is inserted.

 

Dr. David Stern, Professor and President of the Boyce Thompson Institute for Plant Research (webpage):

Expertise: chloroplast biology, bioenergy and nuclear-cytoplasmic interactions.

“In the early days of plant genetic engineering, it was easy to distinguish a ‘GMO’ from a ‘conventional’ plant, because GMOs generally sported traits that distinguished them dramatically from their forebears, such as resistance to Roundup or immunity to caterpillars (Bt). Conventional breeding, on the other hand, was used to gradually increase yield through an iterative “black box” process lasting a decade or more. As expertly described in the TIPS paper, technology has outpaced (or outflanked) these black-and-white categorizations, leaving the organic community at a crossroads regarding how to best achieve its vision for food production. Should it accept newer, more precise technologies, or should it hew to technicalities that would keep it ‘pure’ from the intrusions of DNA jockeys?  The authors play both sides of this debate, and in doing so help readers understand the morass of regulations, and the emotional ties to food that ultimately define our choices in the grocery aisle. 

“When the authors say ‘precision breeding.. may not necessarily be considered to produce GMOs in the USA’ they are referring to the fact that the U.S. tends to regulate by product (the end result) rather than process (how a new variety is produced). It has been argued that some are taking advantage of a so-called loophole to bring what are in fact GMOs to market; others suggest that it is lowering the barrier to entry for entrepreneurs and making a broader range of potentially healthier products accessible to consumers. The authors do a good job of covering the nuance that the organic community could (but not necessarily should) find grounds to reject these products developed with newer technologies because at some stage, recombinant DNA technology is required to make them.”

 

Dr. Norman C. Ellstrand, Professor of Genetics, University of California, Riverside (webpage):

Expertise: The Significance of Gene Flow as an Evolutionary Force; Applied Plant Population Genetics.

“There’s a good point being made here – what the authors call precision breeding is a whole lot more efficient way of delivering a trait to a crop plant than traditional introgression breeding and for single gene traits it’s much more efficient than marker assisted selection. With precision breeding you don’t bring the genetic garbage along with your trait of interest when you’re breeding a new variety. And certainly using a trait from a plant species that’s closely related rather than a distant one (or very distant, such as a bacterium) means the gene expression should be more predictable.

“However, while the thrust of the argument that precision breeding could be used to create improved crop varieties, which could arguably be used in organic agriculture, is valid the authors have used some important terminology loosely, which undermines their effort to bring clarity to the discussion.

“In particular, the way the authors discuss ‘rewilding’ is radically different from the way the term is commonly used. Rewilding is usually used by conservationists to mean returning an ecosystem to its state prior to human disturbance, which is very different from the process the authors describe of adding back beneficial traits of wild plants that have been lost as agricultural crop varieties have been domesticated. Even the first line of the paper – ‘organic farming is based on the concept of working ‘with nature’ instead of against it’ – does not reflect that what is considered organic in the U.S. is based on specific criteria laid down by the USDA.

“Given that these terms are being used loosely, can the authors expect an organic farmer who’s opposed to GM find the precision breeding technique any more palatable than any other genetic engineering technique? For many people who support organics in the U.S. the answer is probably no.”

 

Dr. David Zilberman, Professor of Agricultural & Resource Economics, University of California, Berkeley (webpage):

Expertise: agricultural and environmental policy, marketing, risk management, the economics of innovation, natural resources, water, biotechnology, and biofuels.

“I buy the author’s perspective, and I believe the approach of modifying crops through gene editing is compatible with organic agriculture. In my view, GMOs and organic can make the world a better place, reduce the need for pesticides, increase productivity, and enable us to address the challenges of climate change. The definition of organic is not scientific, rather political, and since the approach described in the paper is more natural than transferring genes between species, they may be able to convince the organic community that it is kosher.

“As an economist working on food issues and the environment, I am alarmed by how much we lose in terms of productivity and greenhouse gas emissions and resource waste because of the politics surrounding organic farming. I am convinced that some of the groups that have the political muscle to define what is and is not organic are aware of these costs, yet they are afraid that if they “give up,” it will allow the introduction of GMOs and other technologies that they dislike. We welcome scientific breakthroughs, and I hope it will be embraced. In any case, in the long run biodiversity will only be enhanced through better understanding and utilization of genetic tools.”

 

Dr. Julie Dawson, Assistant Professor in the Department of Horticulture, University of Wisconsin-Madison (webpage):

Expertise: organic agriculture, participatory research, plant breeding, agrobiodiversity conservation.

“New genetic tools and methods of using genetic information in breeding are needed, for both conventional and organic agriculture, but many of the claims the authors make about gene editing technology are speculative at this point.  

“Many of the traits needed in organic agriculture, including tolerance to biotic and abiotic stress, are quantitative in nature. These traits are not immediately amenable to gene editing, as phenotypes are determined by many genes and gene interactions with the environment.  Single gene disease resistance is an exception to this, however, it is often overcome by pathogen evolution within a fairly short time period, requiring continued deployment of new resistance genes.  

“Many of the claims the authors make about gene editing technology were also made 20 years ago about marker assisted selection, and while marker assisted selection has found a solid place in many breeding programs it has not been the panacea that many molecular geneticists claimed.  

“One of the questions that needs to be asked is whether this is cost-effective, given very limited budgets for all plant breeding in the public sector and limited budgets for organic plant breeding in the private sector.  While gene editing may be very precise for single gene traits, and faster than marker-assisted backcrossing once the gene has been identified (a non-trivial process), organic agriculture might benefit more from classical phenotypic selection for traits of interest in organic systems.  Phenotypic selection is effective, and can work on multiple traits at once — including quantitative traits and those that show considerable genotype by environment interaction. While gene editing is an interesting area of research, this article does not present a convincing argument to pursue it as a primary strategy in breeding for organic systems.”

 

Reference

Feasibility of new breeding techniques for organic farming” by Anderson et al, published in Trends in Plant Science on Thursday 28 May, 2015.

 

Declared interests (see GENeS register of interests policy)

Dr. David Zilberman: I was a paid Scientific Advisor for Monsanto. For several years, I was on the Economic Advisory Board that was part of the U.S. EPA Advisory Board. In addition, I have done consulting for FAO, Mars, Inc., and other organizations. I received grants from USDA, EPA, and various environmental groups.

Dr. David Stern: I have received grants from, and consulted for, the DOE, USDA and NSF. I am also on the External Scientific Advisory Board for the Ohio State University Center for Applied Plant Sciences

No other interests declared.

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