2010 - 2009 - 2008 publications


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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.

Authors

Gonthier L, Bellec A, Blassiau C, Prat E, Helmstetter N, Rambaud C, Huss B, Hendriks T, Bergès H, Quillet MC.

BMC Res Notes. 2010 Aug 11;3:225.


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Abstract

As part of a research programme focused on flavonoid biosynthesis in the seed coat of Brassica napus L. (oilseed rape), orthologs of the BANYULS gene that encoded anthocyanidin reductase were cloned in B. napus as well as in the related species Brassica rapa and Brassica oleracea. B. napus genome contained four functional copies of BAN, two originating from each diploid progenitor. Amino acid sequences were highly conserved between the Brassicaceae including B. napus, B. rapa, B. oleracea as well as the model plant Arabidopsis thaliana. Along the 200 bp in 5' of the ATG codon, Bna.BAN promoters (ProBna.BAN) were conserved with AtANR promoter and contained putative cis-acting elements. In addition, transgenic Arabidopsis and oilseed rape plants carrying the first 230 bp of ProBna.BAN fused to the UidA reporter gene were generated. In the two Brassicaceae backgrounds, ProBna.BAN activity was restricted to the seed coat. In B. napus seed, ProBna.BAN was activated in procyanidin-accumulating cells, namely the innermost layer of the inner integument and the micropyle-chalaza area. At the transcriptional level, the four Bna.BAN genes were expressed in the seed. Laser microdissection assays of the seed integuments showed that Bna.BAN expression was restricted to the inner integument, which was consistent with the activation profile of ProBna.BAN. Finally, Bna.BAN genes were mapped onto oilseed rape genetic maps and potential co-localisations with seed colour quantitative trait loci are discussed.

Planta. 2009 Sep 17 - Auger et al.

 

Authors

Bathilde Auger, Cécile Baron, Marie-Odile Lucas, Sonia Vautrin, Hélène Bergès, Boulos Chalhoub, Alain Fautrel, Michel Renard, Nathalie Nesi.

Planta. 2009 Sep 17.


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Abstract

Most elite wheat varieties cannot be crossed with related species thereby restricting greatly the germplasm that can be used for alien introgression in breeding programs. Inhibition to crossability is controlled genetically and a number of QTL have been identified to date, including SKr, a strong QTL affecting crossability between wheat and rye located at the distal end of chromosome 5BS. In this study, we used a recombinant SSD population originating from a cross between the poorly crossable cultivar Courtot and the crossable line MP98 to characterize the major dominant effect of SKr and map the gene at the distal end of the chromosome near the 5B homoeologous GSP locus. Colinearity with barley and rice was used to saturate the SKr region with new markers and establish orthologous relationships with a 52 kb region on rice chromosome 12. In total, five markers were mapped within a genetic interval of 0.3 cM and 400 kb of BAC contigs were established on both sides of the gene to lay the foundation for map-based cloning of SKr. Two SSR markers completely linked to SKr were used to evaluate a collection of crossable wheat progenies originating from primary triticale breeding programs. The results confirm the major effect of SKr on crossability and the usefulness of the two markers for the efficient introgression of crossability in elite wheat varieties.

 

Authors

Alfares W, Bouguennec A, Balfourier F, Gay G, Bergès H, Vautrin S, Sourdille P, Bernard M, Feuillet C.

Genetics. 2009 Aug 3.

A glimpse into the impossible: chromosome based physical mapping of the giant bread wheat genome.

SCIENCE Vol 322-3 October 2008-Etienne Paux, et al.

Added on : 21 October 2008

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Abstract

The construction of the first physical map of a hexaploid wheat chromosome, 3B (~1Gb), demonstrates that physical mapping in large, complex, and highly repetitive genomes can be performed successfully with a chromosome-based strategy. As part of the international effort to sequence the hexaploid bread wheat genome (Triticum aestivum L.), we constructed a BAC-based physical map of the largest chromosome, 3B (995 Mb, ~1/3 human genome). Using a chromosome-specific BAC library, we assembled 82 % of the chromosome into 1,036 contigs and anchored 65 percent with markers, providing a major resource for structural, functional, and comparative genomic studies as well as for the development of efficient molecular tools for breeders. This first physical map establishes a template for completing the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes using a chromosome-based approach.

SCIENCE Vol 322-3 October 2008-Etienne Paux, et al.

Press Release

 

Authors

Etienne Paux, Pierre Sourdille, Jérôme Salse, Cyrille Saintenac, Frédéric Choulet, Philippe Leroy, Abraham Korol, Monika Michalak, Shahryar Kianian, Wolfgang Spielmeyer, Evans Lagudah, Daryl Somers, Andrzej Kilian, Michael Alaux, Sonia Vautrin, Hélène Bergès, Kellye Eversole, Rudi Appels, Jan Safar, Hana Simkova, Jaroslav Dolezel, Michel Bernard, Catherine Feuillet.