title: miR393 contributes to the embryogenic transition induced in vitro in Arabidopsis via the modification of the tissue sensitivity to auxin treatment.
abstract: miR393 was found to control embryogenic transition in somatic cells in Arabidopsis via control of the TIR1 and AFB2 auxin receptors genes of the F-box family. miR393 molecules are believed to regulate the expression of the auxin receptors of the TAAR clade. Considering the central role of auxin in the induction of somatic embryogenesis (SE) in plant explants cultured in vitro, the involvement of miR393 in the embryogenic transition of somatic cells has been hypothesised. To verify this assumption, the reporter, overexpressor and mutant lines in genes encoded MIR393 and TIR1/AFB proteins of the F-box family were analysed during SE in Arabidopsis. Expression profiling of MIR393a and MIR393b, mature miR393 and the target genes (TIR1, AFB1, AFB2, AFB3) were investigated in explants undergoing SE. In addition, the embryogenic potential of various genotypes with a modified activity of the MIR393 and TIR1/AFB targets was evaluated. The distinct increase in the accumulation of miR393 that was coupled with a notable down-regulation of TIR1 and AFB2 targets was observed at the early phase of SE induction. Relevant to this observation, the GUS/GFP monitored expression of MIR393, TIR1 and AFB2 transcripts was localised in explant tissue undergoing SE induction. The results suggest the miR393-mediated regulation of TIR1 and AFB2 during embryogenic transition induced in Arabidopsis and a modification of the explant sensitivity to auxin treatment is proposed as underlying this regulatory pathway.
authors.affiliation: Department of Genetics, University of Silesia, Jagiellońska 28, 40-032, Katowice, Poland.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Wójcik
authors.affiliation: Department of Genetics, University of Silesia, Jagiellońska 28, 40-032, Katowice, Poland. mmdgaj@us.edu.pl.
authors.forename: Małgorzata D
authors.initials: MD
authors.lastname: Gaj
mesh_terms: D017360:Arabidopsis / Q000196:embryology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics; D015536:Down-Regulation; D044783:F-Box Proteins / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007210:Indoleacetic Acids / Q000494:pharmacology*; D035683:MicroRNAs / Q000235:genetics*; D010937:Plant Growth Regulators / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011956:Receptors, Cell Surface / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000196:embryology / Q000378:metabolism; D046509:Tissue Culture Techniques
chemical_list: C000603490:AFB2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D007210:Indoleacetic Acids; C559857:MIRN393 microRNA, Arabidopsis; D035683:MicroRNAs; D010937:Plant Growth Regulators; D011956:Receptors, Cell Surface; C501405:TIR1 protein, Arabidopsis
keywords: AUXIN F-BOX PROTEIN (AFB); Auxin receptors; MIRNA; Somatic embryogenesis; TRANSPORT INHIBITOR1 (TIR1); miRNA