Surveying the occurrence of subspontaneous glyphosate-tolerant genetically engineered Brassica napus L. (Brassicaceae) along Swiss railways

Abstract

Background: Railway tracks represent a highly interlinked habitat with numerous possibilities for accidental entry of oilseed rape due to seed spill during transportation. Moreover, glyphosate is regularly employed to control the vegetation, increasing the possibility of establishment for plants resistant to it. We surveyed the presence of genetically engineered glyphosate tolerant oilseed rape (Brassica napus) with a focus on the most important Swiss railway stations. Our objective was to detect accidental establishment of transgenic plants, since Switzerland does not import nor cultivate transgenic oilseed rape. Results: Seventy-nine railway areas were sampled in Switzerland and the Principality of Liechtenstein, and the feral presence of oilseed rape was detected in 58 of them. A total of 2403 individuals were tested for genetic modification using commercially available immunologic test kits. In four localities, one located in Lugano and three in the area of Basel, a total of 50 plants expressing the CP4 EPSPS protein were detected. In two of the localities, survival of herbicide applications was observed. The populations were probably introduced through contaminated seed spills from freight trains, or during the transfer of goods from cargo ships to trains. Conclusions: Railways represent an ideal system for herbicide resistant transgenic plants to establish and spread as a result of high selective pressure in favour of herbicide resistance with consequent increased difficulties to keep the infrastructure free of weeds. Crop-to-wild gene flow can occur as several sexually compatible species which are congeneric or in allied genera to oilseed rape were found growing sympatrically. Moreover, the capillary presence of railways in the agricultural landscape provides a putative source of contamination of GE-free agriculture. Our results suggests that carefully adapted monitoring designs may be set in order to detect introduction events that can lead to rapid establishment and growing populations as the accepted contamination thresholds are likely to be biologically insufficient to prevent further environmental contamination.

Low level impurities in imported wheat are a likely source of feral transgenic oilseed rape (Brassica napus L.) in Switzerland

“…This moratorium will last at least until the end of 2017 (FASC 2003), and the control and monitoring of feral GM plants is mandatory (FASC 2008). Nevertheless, feral GM OSR has been found repeatedly in Switzerland (Hecht et al 2014;Schoenenberger and D'Andrea 2012;Schulze et al 2014). In the most recent study, the occurrence of feral herbicide resistant GM OSR events GT73 (Roundup Ready, Monsanto), MS8×RF3, MS8 and RF3 (all traded as InVigor, Bayer CropScience) has been reported for the Rhine port of Basel in Switzerland ).…”

Cultivation-independent establishment of genetically engineered plants in natural populations: current evidence and implications for EU regulation

“…From existing data, it can be concluded that maize (Zea mays) in Mexico [3,4,[38][39][40][41] and oilseed rape (B. napus) in the USA [42], Australia [43,44] and Europe [45][46][47] are likely to have escaped regulatory control, but it is unclear to which extent gene flow to wild relatives has already occurred. Finally, in the cases of rice (Oryza sativa) in China [48,49], black poplar (Populus nigra) in China [50][51][52] and papaya (Carica papaya) in Thailand [53], it can be expected that transgenes will introgress natural populations, though evidence is not yet available.…”

How to track genetically modified (GM) plants in the field? The VDI standard method of floristic mapping of GM plants as an efficient tool

“…Conventional and GM oilseed rape can establish feral (spontaneous or subspontaneous) populations on various types of non-cropped land (Pessel et al 2001, Yoshimura et al 2006, Elling 2008, Elling et al 2009, Kawata et al 2009, Nishizawa et al 2009, Schafer et al 2011, Schoenenberger and D'Andrea 2012. These populations occur frequently along transportation routes (e.g.…”