title: Small silencing RNAs in plants are mobile and direct epigenetic modification in recipient cells.
abstract: A silencing signal in plants with an RNA specificity determinant moves through plasmodesmata and the phloem. To identify the mobile RNA, we grafted Arabidopsis thaliana shoots to roots that would be a recipient for the silencing signal. Using mutants that block small RNA (sRNA) biogenesis in either source or recipient tissue, we found that transgene-derived sRNA as well as a substantial proportion of the endogenous sRNA had moved across the graft union, and we provide evidence that 24-nucleotide mobile sRNAs direct epigenetic modifications in the genome of the recipient cells. Mobile sRNA thus represents a mechanism for transmitting the specification of epigenetic modification and could affect genome defense and responses to external stimuli that have persistent effects in plants.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
authors.forename: Attila
authors.initials: A
authors.lastname: Molnar
authors.forename: Charles W
authors.initials: CW
authors.lastname: Melnyk
authors.forename: Andrew
authors.initials: A
authors.lastname: Bassett
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hardcastle
authors.forename: Ruth
authors.initials: R
authors.lastname: Dunn
authors.forename: David C
authors.initials: DC
authors.lastname: Baulcombe
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004251:DNA Transposable Elements; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism; D044127:Epigenesis, Genetic; D017343:Genes, Plant; D018745:Genome, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D004251:DNA Transposable Elements; D018744:DNA, Plant; D035683:MicroRNAs; D018749:RNA, Plant; D034741:RNA, Small Interfering