Why Organic Farming Should Embrace Co-Existence with Cisgenic Late Blight–Resistant Potato

Abstract

Abstract:The EU regulation on organic farming does not allow the use of genetically modified organisms (GMOs) which are subject to Directive 2001/18/EC. Mutagenesis using irradiation or chemicals is genetic modification, but the organisms obtained through these techniques are not subject to the provisions of the GMO directive. Such mutants can therefore be used in organic agriculture. Derived from its basic principles, organic farming can only use natural substances to control disease and crops should be resilient, which, in the case of disease resistance, means that durable (horizontal) resistance is preferred to vertical (single gene) resistance. Cisgenesis can achieve such a durable resistance by introducing multiple resistance genes in one step. These multiple-resistant plants only contain natural genes that can also be introduced by breeding. In case cisgenic plants are not subject to the provisions of the GMO legislation, they can even be legally used in organic agriculture. In case they are not exempted from the GMO regulation, the question is: why obstruct a cisgenic potato crop that can hardly be distinguished from a potato crop that is the result of conventional breeding? Among the reasons why organic agriculture does not allow the use of GMOs it is mentioned that genetic engineering is unpredictable, it causes genome disruption and it is unnatural. However, our knowledge of plant genome evolution and breeding has increased dramatically. We now know that breeding is more unpredictable and causes more genome disruption than genetic engineering. Recent field trials have shown the efficacy of cisgenic late blight-resistant potatoes carrying multiple resistance genes. Large-scale growing of such durably resistant potatoes would not only be environmentally beneficial by it would strongly reducing the need for fungicide sprays in conventional potato cultivation and it would also reduce the disease pressure in organic potato cultivation.

I Have a Dream: Organic Movements Include Gene Manipulation to Improve Sustainable Farming

“…However, it took almost half a century to establish the resistant varieties Bionica and Toluca containing a single resistance gene [15]. Gheysen and Custers stress [5] that these breeding strategies involved the use of the chemical colchicine to double the number of chromosomes. The use of this drug violates the nonchemical principle of organic farming and according to some proponents of organic farming, its application should be forbidden [16].…”

“…Gheysen and Custers [5], as well as Pacifico and Paris [6], discuss the potential benefits of potatoes generated by NPBTs. Both groups review the problem of late blight disease caused by the oomycete Phytophthora infestans that infects potatoes and necessitates the application of copper fungicides even in organic farming systems, although copper is a toxic heavy metal whose accumulation in the soils reached dangerous levels in several places.…”

“…This reflects the inclusion of undesired traits by linkage drag in conventional crossings. In contrast, cisgenesis can be performed on a cultivar with desirable agronomic, eating and processing characteristics and will only add disease resistance [5].…”

“…More importantly, the DuRPh researchers at the University of Wageningen (Netherlands) that patented the isolated genes foresee exploitation through non-exclusive licenses to avoid a monopoly that would jeopardize a wider use by small and medium enterprises [17]. Gheysen and Custers [5] mention that the Bionica potato made by conventional breeding for organic production has less desirable characteristics such as lower palatability and inferior processing qualities. This reflects the inclusion of undesired traits by linkage drag in conventional crossings.…”

“…To address the problem of whether organic farming and gene manipulation may be compatible, I initiated a Special Issue in Sustainability by inviting experts of both fields to express their views on this topic [1][2][3][4][5][6][7]. I am most thankful to all contributors for joining this discussion, but also to the reviewers for evaluating these manuscripts.…”