title: The MdTFL1 gene of apple (Malus x domestica Borkh.) reduces vegetative growth and generation time.
abstract: TFL1 is known as a floral repressor in Arabidopsis thaliana (L.) Heynh. In apple there are two TFL1 homologs, MdTFL1-1 and MdTFL1-2. The MdTFL1-1 gene was silenced in transgenic clones expressing a hairpin gene construct of a 323 bp fragment of MdTFL1-1. The hairpin gene construct was transferred to three different apple genotypes. Of 22 transgenic clones, 21 showed a significant reduction in MdTFL1-1 mRNA expression. Precocious flowering was obtained for 20 clones, which flowered already during in vitro cultivation. Nineteen clones could successfully be transferred to the greenhouse where 18 of them flowered within a few weeks followed by the death or at least a strongly inhibited vegetative growth of the plant. Most of the transgenic flowers developed abnormally. Results obtained on greenhouse-grown plants of the transgenic clones and transgenic seedlings clearly demonstrated the major role of MdTFL1 genes in maintaining the vegetative growth as prerequisite for a perennial lifecycle. It was shown that MdTFL1 dsRNAi promotes a life history similar to annual plants. Preliminary results obtained from grafting experiments with non-transgenic scions grafted onto MdTFL1 dsRNAi transgenic rootstocks indicated that the flower-inducing signal obtained after silencing of MdTFL1 genes seems not to be graft-transmissible.
authors.affiliation: Julius Kühn-Institute - Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Horticultural and Fruit Crops, Pillnitzer Platz 3a, D-01326 Dresden, Germany.
authors.forename: Henryk
authors.initials: H
authors.lastname: Flachowsky
authors.forename: Iris
authors.initials: I
authors.lastname: Szankowski
authors.forename: Sascha
authors.initials: S
authors.lastname: Waidmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Peil
authors.forename: Conny
authors.initials: C
authors.lastname: Tränkner
authors.forename: Magda-Viola
authors.initials: MV
authors.lastname: Hanke
mesh_terms: D018744:DNA, Plant / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D027845:Malus / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D054817:Pollination; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D036226:Seedlings / Q000235:genetics / Q000254:growth & development; D013997:Time Factors; D019076:Transgenes
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant