title: Long-term stability of marker gene expression in Prunus subhirtella: a model fruit tree species.
abstract: Transgenic trees currently are being produced by Agrobacterium-mediated transformation and biolistics. Since trees are particularly suited for long-term evaluations of the impact of the technology, Prunus subhirtella autumno rosa (PAR) was chosen as model fruit tree species and transformed with a reporter gene (uidA) under the control of the 35S promoter. Using Southern and GUS fluorometric techniques, we compared transgene copy numbers and observed stability of transgene expression levels in 34 different transgenic plants, grown under in vitro, greenhouse and screenhouse conditions, over a period of 9 years. An influence of grafting on gene expression was not observed. No silenced transgenic plant was detected. Overall, these results suggest that transgene expression in perennial species, such as fruit trees, remains stable in time and space, over extended periods and in different organs, confirming the value of PAR as model species to study season-dependent regulation in mature stone fruit tissues. While the Agrobacterium-derived Prunus transformants contained one to two copies of the transgenes, 91% of the transgenic events also contained various lengths of the bacterial plasmid backbone, indicating that the Agrobacterium-mediated transformation is not as precise as previously perceived. The implications for public acceptance and future applications are discussed.
authors.affiliation: Plant Biotechnology Unit, Institute of Applied Microbiology, Department of Biotechnology, BOKU, Nussdorfer Läende 11, A-1190 Vienna, Austria.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Maghuly
authors.forename: Artur
authors.initials: A
authors.lastname: da Câmara Machado
authors.forename: Stephan
authors.initials: S
authors.lastname: Leopold
authors.forename: Mahmood Ali
authors.initials: MA
authors.lastname: Khan
authors.forename: Hermann
authors.initials: H
authors.lastname: Katinger
authors.forename: Margit
authors.initials: M
authors.lastname: Laimer
mesh_terms: D001483:Base Sequence; D015139:Blotting, Southern; D004269:DNA, Bacterial / Q000378:metabolism; D018744:DNA, Plant / Q000378:metabolism; D018628:Gene Dosage; D015870:Gene Expression; D017343:Genes, Plant; D005819:Genetic Markers / Q000235:genetics; D008957:Models, Genetic; D030821:Plants, Genetically Modified; D027861:Prunus / Q000235:genetics*; D013997:Time Factors; D014170:Transformation, Genetic; D019076:Transgenes; D014197:Trees / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D018744:DNA, Plant; D005819:Genetic Markers; C036483:T-DNA