title: Construction and characterization of two BAC libraries representing a deep-coverage of the genome of chicory (Cichorium intybus L., Asteraceae).
abstract: BACKGROUND
  The Asteraceae represents an important plant family with respect to the numbers of species present in the wild and used by man. Nonetheless, genomic resources for Asteraceae species are relatively underdeveloped, hampering within species genetic studies as well as comparative genomics studies at the family level. So far, six BAC libraries have been described for the main crops of the family, i.e. lettuce and sunflower. Here we present the characterization of BAC libraries of chicory (Cichorium intybus L.) constructed from two genotypes differing in traits related to sexual and vegetative reproduction. Resolving the molecular mechanisms underlying traits controlling the reproductive system of chicory is a key determinant for hybrid development, and more generally will provide new insights into these traits, which are poorly investigated so far at the molecular level in Asteraceae.
  
  
  RESULTS
  Two bacterial artificial chromosome (BAC) libraries, CinS2S2 and CinS1S4, were constructed from HindIII-digested high molecular weight DNA of the contrasting genotypes C15 and C30.01, respectively. C15 was hermaphrodite, non-embryogenic, and S2S2 for the S-locus implicated in self-incompatibility, whereas C30.01 was male sterile, embryogenic, and S1S4. The CinS2S2 and CinS1S4 libraries contain 89,088 and 81,408 clones. Mean insert sizes of the CinS2S2 and CinS1S4 clones are 90 and 120 kb, respectively, and provide together a coverage of 12.3 haploid genome equivalents. Contamination with mitochondrial and chloroplast DNA sequences was evaluated with four mitochondrial and four chloroplast specific probes, and was estimated to be 0.024% and 1.00% for the CinS2S2 library, and 0.028% and 2.35% for the CinS1S4 library. Using two single copy genes putatively implicated in somatic embryogenesis, screening of both libraries resulted in detection of 12 and 13 positive clones for each gene, in accordance with expected numbers.
  
  
  CONCLUSIONS
  This indicated that both BAC libraries are valuable tools for molecular studies in chicory, one goal being the positional cloning of the S-locus in this Asteraceae species.
authors.affiliation: Univ Lille Nord de France, F-59000 Lille, France, Stress Abiotiques et Différenciation des Végétaux Cultivés (SADV), UMR INRA-USTL 1281, Bât, SN2, F-59655 Villeneuve d'Ascq, France. helene.berges@toulouse.inra.fr.
authors.forename: Lucy
authors.initials: L
authors.lastname: Gonthier
authors.forename: Arnaud
authors.initials: A
authors.lastname: Bellec
authors.forename: Christelle
authors.initials: C
authors.lastname: Blassiau
authors.forename: Elisa
authors.initials: E
authors.lastname: Prat
authors.forename: Nicolas
authors.initials: N
authors.lastname: Helmstetter
authors.forename: Caroline
authors.initials: C
authors.lastname: Rambaud
authors.forename: Brigitte
authors.initials: B
authors.lastname: Huss
authors.forename: Theo
authors.initials: T
authors.lastname: Hendriks
authors.forename: Hélène
authors.initials: H
authors.lastname: Bergès
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Quillet