title: Global and local perturbation of the tomato microRNA pathway by a trans-activated DICER-LIKE 1 mutant.
abstract: DICER-like 1 (DCL1) is a major player in microRNA (miRNA) biogenesis and accordingly, its few known loss-of-function mutants are either lethal or display arrested development. Consequently, generation of dcl1 mutants by reverse genetics and functional analysis of DCL1 in late-developing organs are challenging. Here, these challenges were resolved through the unique use of trans-activated RNA interference. Global, as well as organ-specific tomato DCL1 (SlDCL1) silencing was induced by crossing the generated responder line (OP:SlDCL1IR) with the appropriate driver line. Constitutive trans-activation knocked down SlDCL1 levels by ~95%, resulting in severe abnormalities including post-germination growth arrest accompanied by decreased miRNA and 21-nucleotide small RNA levels, but prominently elevated levels of 22-nucleotide small RNAs. The increase in the 22-nucleotide small RNAs was correlated with specific up-regulation of SlDCL2b and SlDCL2d, which are probably involved in their biogenesis. Leaf- and flower-specific OP:SlDCL1IR trans-activation inhibited blade outgrowth, induced premature bud senescence and produced pale petals, respectively, emphasizing the importance of SlDCL1-dependent small RNAs in these processes. Together, these results establish OP:SlDCL1IR as an efficient tool for analysing processes regulated by SlDCL1-mediated gene regulation in tomato.
authors.affiliation: Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, PO Box 6, Bet Dagan 50250, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Kravchik
authors.forename: Ramanjulu
authors.initials: R
authors.lastname: Sunkar
authors.forename: Subha
authors.initials: S
authors.lastname: Damodharan
authors.forename: Ran
authors.initials: R
authors.lastname: Stav
authors.forename: Matat
authors.initials: M
authors.lastname: Zohar
authors.forename: Tal
authors.initials: T
authors.lastname: Isaacson
authors.forename: Tzahi
authors.initials: T
authors.lastname: Arazi
mesh_terms: D001483:Base Sequence; D002338:Carotenoids / Q000378:metabolism; D035264:Flowers / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017930:Genes, Reporter; D018551:Solanum lycopersicum / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics; D010940:Plant Proteins / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D043244:Ribonuclease III / Q000378:metabolism*; D036226:Seedlings / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015533:Transcriptional Activation / Q000235:genetics*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D035683:MicroRNAs; D010940:Plant Proteins; D018749:RNA, Plant; D034741:RNA, Small Interfering; D002338:Carotenoids; D043244:Ribonuclease III
keywords: Carotenoid; DCL1; leaf; miRNA; mutant; petal; tomato.