title: RNA-mediated gene silencing signals are not graft transmissible from the rootstock to the scion in greenhouse-grown apple plants Malus sp.
abstract: RNA silencing describes the sequence specific degradation of RNA targets. Silencing is a non-cell autonomous event that is graft transmissible in different plant species. The present study is the first report on systemic acquired dsRNA-mediated gene silencing of transgenic and endogenous gene sequences in a woody plant like apple. Transgenic apple plants overexpressing a hairpin gene construct of the gusA reporter gene were produced. These plants were used as rootstocks and grafted with scions of the gusA overexpressing transgenic apple clone T355. After grafting, we observed a reduction of the gusA gene expression in T355 scions in vitro, but not in T355 scions grown in the greenhouse. Similar results were obtained after silencing of the endogenous Mdans gene in apple that is responsible for anthocyanin biosynthesis. Subsequently, we performed grafting experiments with Mdans silenced rootstocks and red leaf scions of TNR31-35 in order to evaluate graft transmitted silencing of the endogenous Mdans. The results obtained suggested a graft transmission of silencing signals in in vitro shoots. In contrast, no graft transmission of dsRNA-mediated gene silencing signals was detectable in greenhouse-grown plants and in plants grown in an insect protection tent.
authors.affiliation: Julius Kühn-Institute-Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Horticultural and Fruit Crops, Dresden 01326, Germany.
authors.forename: Henryk
authors.initials: H
authors.lastname: Flachowsky
authors.affiliation: Plant Breeding Institute, Christian-Albrechts-University of Kiel, Kiel 24098, Germany.
authors.forename: Conny
authors.initials: C
authors.lastname: Tränkner
authors.affiliation: Division Surgical Research, Regenerative Medicine Program, University and University Hospital Zurich, Zurich 8001, Switzerland.
authors.forename: Iris
authors.initials: I
authors.lastname: Szankowski
authors.affiliation: Gregor Mendel Institute for Molecular Plant Biology GmbH, Vienna 2000-2419, Austria.
authors.forename: Sascha
authors.initials: S
authors.lastname: Waidmann
authors.affiliation: Julius Kühn-Institute-Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Horticultural and Fruit Crops, Dresden 01326, Germany.
authors.forename: Magda-Viola
authors.initials: MV
authors.lastname: Hanke
authors.affiliation: Unit of Fruit Science, Department for Plant Sciences, Technical University Munich, Freising 85356, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Treutter
authors.affiliation: Plant Biochemistry and Physiology, Biocenter Botany, Ludwig-Maximilians-University Munich, Planegg-Martinsried 82152, Germany.
authors.forename: Thilo C
authors.initials: TC
authors.lastname: Fischer
mesh_terms: D016960:Agrobacterium tumefaciens / Q000502:physiology; D060467:Disease Resistance / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D027845:Malus / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics*; D018517:Plant Roots / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering