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Construction and characterization of two BAC libraries representing a deep-coverage of the genome of chicory (Cichorium intybus L., Asteraceae)

Lucy Gonthier1, Arnaud Bellec2, Christelle Blassiau1, Elisa Prat2, Nicolas Helmstetter2, Caroline Rambaud1, Brigitte Huss1, Theo Hendriks1, Hélène Bergès2* and Marie-Christine Quillet1*

Author Affiliations

1 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

2 Centre National des Ressources Génomiques Végétales (CNRGV), INRA, Chemin de Borde Rouge, BP 52627, F-31326 Castanet Tolosan, France

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BMC Research Notes 2010, 3:225  doi:10.1186/1756-0500-3-225

Published: 11 August 2010

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.

Findings

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.