title: Graft-transmissible movement of inverted-repeat-induced siRNA signals into flowers.
abstract: In plants, small interfering RNAs (siRNA) and microRNAs move to distant tissues where they control numerous developmental and physiological processes such as morphogenesis and stress responses. Grafting techniques and transient expression systems have been employed to show that sequence-specific siRNAs with a size of 21-24 nucleotides traffic to distant organs. We used inverted-repeat constructs producing siRNA targeting the meiosis factor DISRUPTED MEIOTIC cDNA 1 (DMC1) and GFP to test whether silencing signals move into meiotically active tissues. In grafted Nicotiana tabacum, a transgenic DMC1 siRNA signal made in source tissues preferably entered the anthers formed in the first flowers. Here, the DMC1 siRNA interfered with meiotic progression and, consequently, the flowers were at least partially sterile. In agro-infiltrated N. benthamiana plants, a GFP siRNA signal produced in leaves was allocated and active in most flower tissues including anthers. In hypocotyl-grafted Arabidopsis thaliana plants, the DMC1 silencing signal consistently appeared in leaves, petioles, and stem, and only a small number of plants displayed DMC1 siRNA signals in flowers. In all three tested plant species the systemic silencing signal penetrated male sporogenic tissues suggesting that plants harbour an endogenous long-distance small RNA transport pathway facilitating siRNA signalling into meiotically active cells.
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, Golm, Germany.
authors.forename: Wenna
authors.initials: W
authors.lastname: Zhang
authors.forename: Gregor
authors.initials: G
authors.lastname: Kollwig
authors.forename: Ewelina
authors.initials: E
authors.lastname: Stecyk
authors.forename: Federico
authors.initials: F
authors.lastname: Apelt
authors.forename: Rob
authors.initials: R
authors.lastname: Dirks
authors.forename: Friedrich
authors.initials: F
authors.lastname: Kragler
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D035264:Flowers / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing; D017930:Genes, Reporter; D008540:Meiosis / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D018613:Microscopy, Confocal; D009928:Organ Specificity; D010641:Phenotype; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011058:Pollen / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics*; D011938:Rec A Recombinases / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D035683:MicroRNAs; D034741:RNA, Small Interfering; C513034:ATDMC1 protein, Arabidopsis; D011938:Rec A Recombinases
keywords: RNA signalling; anthers; doubled haploids; flower; grafting; meiosis; ovules; phloem; siRNA