Assessment of the potential for gene flow from transgenic maize (Zea mays L.) to eastern gamagrass (Tripsacum dactyloides L.)

Abstract

Eastern gamagrass (Tripsacum dactyloides L.) belongs to the same tribe of the Poaceae family as maize (Zea mays L.) and grows naturally in the same region where maize is commercially produced in the USA. Although no evidence exists of gene flow from maize to eastern gamagrass in nature, experimental crosses between the two species were produced using specific techniques. As part of environmental risk assessment, the possibility of transgene flow from maize to eastern gamagrass populations in nature was evaluated with the objectives: (1) to assess the seeds of eastern gamagrass populations naturally growing near commercial maize fields for the presence of a transgenic glyphosate-tolerance gene (cp4 epsps) that would indicate cross-pollination between the two species, and (2) to evaluate the possibility of interspecific hybridization between transgenic maize used as male parent and eastern gamagrass used as female parent. A total of 46,643 seeds from 54 eastern gamagrass populations collected in proximity of maize fields in Illinois, USA were planted in a field in 2014 and 2015. Emerged seedlings were treated with glyphosate herbicide and assessed for survival. An additional 48,000 seeds from the same 54 eastern gamagrass populations were tested for the presence of the cp4 epsps transgene markers using TaqMan® PCR method. The results from these trials showed that no seedlings survived the herbicide treatment and no seed indicated presence of the herbicide tolerant cp4 epsps transgene, even though these eastern gamagrass populations were exposed to glyphosate-tolerant maize pollen for years. Furthermore, no interspecific hybrid seeds were produced from 135 hand-pollination attempts involving 1529 eastern gamagrass spikelets exposed to maize pollen. Together, these results indicate that there is no evidence of gene flow from maize to eastern gamagrass in natural habitats. The outcome of this study should be taken in consideration when assessing for environmental risks regarding the consequence of gene flow from transgenic maize to its wild relatives.Electronic supplementary materialThe online version of this article (doi:10.1007/s11248-017-0020-7) contains supplementary material, which is available to authorized users.

Tripsazea, a Novel Trihybrid of Zea mays, Tripsacum dactyloides, and Zea perennis

“…However, it is not easy to synthesize Tripsacum bridges by traditional crossing, even when combined with the embryo rescue technique. In a recent study, a total of 94,643 seeds from 54 eastern gamagrass populations exposed in n■ proximity to glyphosate-tolerant maize fields were evaluated by a glyphosate-tolerant test and transgene marker (Lee et al 2017). Their results indicated that natural hybridization between Tripsacum and maize is impossible.…”

Adaptation analysis of insect-resistant transgenic line after introducing mcry1F gene in maize

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To meet the growing global demand for food, fibre, and fuel, innovative transgenic technology has become widely used worldwide (Lee et al 2017, ISAAA 2018). Among the most important grain crops globally, maize was also one of the first crops to be developed as a transgenic cultivar to achieve resistance to insects, herbicides, and adverse environments through transgenic technology.

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Risks of Pollen-Mediated Gene Flow From Genetically Modified Maize During Co-Cultivation With Usual Maize Varieties

“…Гамаграсс восточный принадлежит к тому же роду семейства Poaceae, что и кукуруза Zea mays L., и произрастает естественным образом в том же регионе США, где коммерчески производится кукуруза. Для исследования потока генов от кукурузы к гамаграссу были произведены экспериментальные скрещивания между между трансгенной кукурузой, используемой в качестве мужского родителя, и гамаграссом в качестве женского с целью оценить возможность межвидовой гибридизации (66). Никаких доказательств потока генов из транс-генной кукурузы в гамаграсс восточный в природе не наблюдали, хотя эти два вида росли в непосредственной близости в течение многих лет и имели широкие возможности для скрещивания (66).…”