title: Directed microspore-specific recombination of transgenic alleles to prevent pollen-mediated transmission of transgenes.
abstract: A major challenge for future genetically modified (GM) crops is to prevent undesired gene flow of transgenes to plant material intended for another use. Recombinase-mediated auto excision of transgenes directed by a tightly controlled microspore-specific promoter allows efficient removal of either the selectable marker gene or of all introduced transgenes during microsporogenesis. This way, transgene removal becomes an integral part of the biology of pollen maturation, not requiring any external stimulus such as chemical induction by spraying. We here show the feasibility of engineering transgenic plants to produce pollen devoid of any transgene. Highly efficient excision of transgenes from tobacco pollen was achieved with a potential failure rate of at most two out of 16,800 seeds (0.024%). No evidence for either premature activation or absence of activation of the recombinase system was observed under stress conditions in the laboratory. This approach can prevent adventitious presence of transgenes in non-GM crops or related wild species by gene flow. Such biological containment may help the deployment and management of coexistence practices to support consumer choice and will promote clean molecular farming for the production of high-value compounds in plants.
authors.affiliation: Plant Sciences Group, Wageningen University and Research Centre, PO Box 16, 6700 AA Wageningen, The Netherlands.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Mlynárová
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Conner
authors.forename: Jan-Peter
authors.initials: JP
authors.lastname: Nap
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics; D051456:Gene Flow; D005818:Genetic Engineering / Q000379:methods; D005819:Genetic Markers; D019426:Integrases / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics*; D010957:Plasmids; D011058:Pollen / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011995:Recombination, Genetic; D014026:Nicotiana / Q000235:genetics*; D019076:Transgenes
chemical_list: D005819:Genetic Markers; C045073:Cre recombinase; D019426:Integrases