title: Development of visible markers for transgenic plants and their availability for environmental risk assessment.
abstract: Monitoring of transgenic plants in the field is important, but risk assessment has entailed laborious use of invisible marker genes. Here, we assessed three easily visible marker transgenes--green fluorescent protein (GFP), R, and Nicotiana tabacum homeobox (NTH) 15 genes--for their potential use as marker genes for monitoring genetically modified plants. Transgenic Arabidopsis thaliana plants for each of these genes were visibly distinguished from wild-type plants. We determined the germination rate, 3-week fresh weight, time to first flowering, and seed weight of the transgenic plants to evaluate whether the expression of these marker genes affected the growth of the host. Introduction of GFP gene had no effect on the evaluated parameters, and we then used the GFP gene as a marker to assess the outcrossing frequency between transgenic and two Arabidopsis species. Our results showed that the hybridization frequency between transgenic plants and Arabidopsis thaliana was 0.24%, and between transformants and Arabidopsis lyrata it was 2.6% under experimental condition. Out-crossing frequency was decreased by extending the distance between two kinds of plants. Thus, the GFP gene is a useful marker for assessing the whereabouts of transgenes/transformants in the field. We also demonstrated that the GFP gene is possibly applicable as a selection marker in the process of generation of transgenic plants.
authors.affiliation: Biodiversity Conservation Research Project, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan. mtamaoki@nies.go.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Tamaoki
authors.forename: Hiroe
authors.initials: H
authors.lastname: Imai
authors.forename: Hayato
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yumio
authors.initials: Y
authors.lastname: Toda
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Niwa
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Nakajima
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Aono
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kubo
authors.forename: Hikaru
authors.initials: H
authors.lastname: Saji
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D015415:Biomarkers / Q000032:analysis*; D004787:Environmental Pollution; D005819:Genetic Markers; D018525:Germination / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000737:chemistry* / Q000502:physiology*; D018570:Risk Assessment; D012639:Seeds / Q000502:physiology; D012641:Selection, Genetic
chemical_list: D015415:Biomarkers; D005819:Genetic Markers; D049452:Green Fluorescent Proteins