title: Identification of the Arabidopsis RAM/MOR signalling network: adding new regulatory players in plant stem cell maintenance and cell polarization.
abstract: OBJECTIVE
  The RAM/MOR signalling network of eukaryotes is a conserved regulatory module involved in co-ordination of stem cell maintenance, cell differentiation and polarity establishment. To date, no such signalling network has been identified in plants.
  
  
  METHODS
  Genes encoding the bona fide core components of the RAM/MOR pathway were identified in Arabidopsis thaliana (arabidopsis) by sequence similarity searches conducted with the known components from other species. The transcriptional network(s) of the arabidopsis RAM/MOR signalling pathway were identified by running in-depth in silico analyses for genes co-regulated with the core components. In situ hybridization was used to confirm tissue-specific expression of selected RAM/MOR genes.
  
  
  RESULTS
  Co-expression data suggested that the arabidopsis RAM/MOR pathway may include genes involved in floral transition, by co-operating with chromatin remodelling and mRNA processing/post-transcriptional gene silencing factors, and genes involved in the regulation of pollen tube polar growth. The RAM/MOR pathway may act upstream of the ROP1 machinery, affecting pollen tube polar growth, based on the co-expression of its components with ROP-GEFs. In silico tissue-specific co-expression data and in situ hybridization experiments suggest that different components of the arabidopsis RAM/MOR are expressed in the shoot apical meristem and inflorescence meristem and may be involved in the fine-tuning of stem cell maintenance and cell differentiation.
  
  
  CONCLUSIONS
  The arabidopsis RAM/MOR pathway may be part of the signalling cascade that converges in pollen tube polarized growth and in fine-tuning stem cell maintenance, differentiation and organ polarity.
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy monica.zermiani@unipd.it benedetto.ruperti@unipd.it.
authors.forename: Monica
authors.initials: M
authors.lastname: Zermiani
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy.
authors.forename: Maura
authors.initials: M
authors.lastname: Begheldo
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Nonis
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 2
authors.forename: Klaus
authors.initials: K
authors.lastname: Palme
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Mizzi
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Morandini
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Nonis
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università, 16, 35020 Legnaro (PD), Italy, University Centre of Statistics for Biomedical Sciences, Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy, Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany, Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany, Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany, Department of BioSciences, University of Milan, Via Celoria 26, 20133 Milan, Italy and CNR Biophysics Institute (Milan Section), Via Celoria 26, 20133 Milan, Italy monica.zermiani@unipd.it benedetto.ruperti@unipd.it.
authors.forename: Benedetto
authors.initials: B
authors.lastname: Ruperti
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity / Q000235:genetics; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D016000:Cluster Analysis; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D017343:Genes, Plant; D017403:In Situ Hybridization; D015398:Signal Transduction / Q000235:genetics*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors; D059467:Transcriptome / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins
keywords: Arabidopsis thaliana; RAM/MOR signalling network; cell polarity; floral transition; in situ hybridization; stem cell maintenance; transcriptional networks