title: Ancestral synteny shared between distantly-related plant species from the asterid (Coffea canephora and Solanum Sp.) and rosid (Vitis vinifera) clades.
abstract: BACKGROUND
  Coffee trees (Rubiaceae) and tomato (Solanaceae) belong to the Asterid clade, while grapevine (Vitaceae) belongs to the Rosid clade. Coffee and tomato separated from grapevine 125 million years ago, while coffee and tomato diverged 83-89 million years ago. These long periods of divergent evolution should have permitted the genomes to reorganize significantly. So far, very few comparative mappings have been performed between very distantly related species belonging to different clades. We report the first multiple comparison between species from Asterid and Rosid clades, to examine both macro-and microsynteny relationships.
  
  
  RESULTS
  Thanks to a set of 867 COSII markers, macrosynteny was detected between coffee, tomato and grapevine. While coffee and tomato genomes share 318 orthologous markers and 27 conserved syntenic segments (CSSs), coffee and grapevine also share a similar number of syntenic markers and CSSs: 299 and 29 respectively. Despite large genome macrostructure reorganization, several large chromosome segments showed outstanding macrosynteny shedding new insights into chromosome evolution between Asterids and Rosids. We also analyzed a sequence of 174 kb containing the ovate gene, conserved in a syntenic block between coffee, tomato and grapevine that showed a high-level of microstructure conservation. A higher level of conservation was observed between coffee and grapevine, both woody and long life-cycle plants, than between coffee and tomato. Out of 16 coffee genes of this syntenic segment, 7 and 14 showed complete synteny between coffee and tomato or grapevine, respectively.
  
  
  CONCLUSIONS
  These results show that significant conservation is found between distantly related species from the Asterid (Coffea canephora and Solanum sp.) and Rosid (Vitis vinifera) clades, at the genome macrostructure and microstructure levels. At the ovate locus, conservation did not decline in relation to increasing phylogenetic distance, suggesting that the time factor alone does not explain divergences. Our results are considerably useful for syntenic studies between supposedly remote species for the isolation of important genes for agronomy.
authors.affiliation: UMR DIADE, Evolution et Dynamique des Génomes, Institut de Recherche pour le Développement (IRD), BP 64501, 34394 Montpellier Cedex 5, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Guyot
authors.forename: Florent
authors.initials: F
authors.lastname: Lefebvre-Pautigny
authors.forename: Christine
authors.initials: C
authors.lastname: Tranchant-Dubreuil
authors.forename: Michel
authors.initials: M
authors.lastname: Rigoreau
authors.forename: Perla
authors.initials: P
authors.lastname: Hamon
authors.forename: Thierry
authors.initials: T
authors.lastname: Leroy
authors.forename: Serge
authors.initials: S
authors.lastname: Hamon
authors.forename: Valérie
authors.initials: V
authors.lastname: Poncet
authors.forename: Dominique
authors.initials: D
authors.lastname: Crouzillat
authors.forename: Alexandre
authors.initials: A
authors.lastname: de Kochko
mesh_terms: D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D003001:Cloning, Molecular; D040503:Coffea / Q000235:genetics; D019295:Computational Biology; D019143:Evolution, Molecular; D056426:Genetic Loci / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D019684:Magnoliopsida / Q000235:genetics*; D010802:Phylogeny; D032322:Solanum / Q000235:genetics; D026801:Synteny; D027843:Vitis / Q000235:genetics