Conférence de Jeffrey J. Doyle

 Olivier Troccaz    17/11/2009 : 12:00
 Aucun    Agenda


Le mardi 17 novembre, à 13h00, salle de conférences du CAREN, campus de Beaulieu, UR1.

Le mardi 17 novembre, à 13h00, salle de conférences du CAREN, campus de Beaulieu, UR1. Recent allopolyploidy in genus Glycine (Fabaceae): Comparative genomics-transcriptomics and evolution of Photosynthesis Résumé : Glycine (Fabaceae) includes the annual species soybean and its wild progenitor (G. max and G. soja) as well as approximately 26 perennial species of subgenus Glycine. The genus is a paleopolyploid, with 2n = 4x = 40 (38). In addition to "diploid" (2n = 38, 40) species, subg. Glycine also includes eight allopolyploid species (2n = 78, 80). We have used various nuclear and plastid DNA sequences to decipher the evolutionary history and origin of the polyploid species. Unlike all diploid species of subg. Glycine, which are confined to Australia, five of the polyploid species have colonized islands of the Pacific Ocean, some of them multiple times. Current research focuses on identifying commonalities among the allopolyploids, in the hope of eventually identifying a unifying feature underlying their ability to colonize. As expected, cell size is larger in polyploids than in diploids. In at least some cases, polyploids have a higher capacity for photoprotection (non-photochemical quenching). We are exploring this by transcriptome sequencing using the Illumina (Solexa) platform, initially on one allopolyploid and its diploid progenitor species. This approach has allowed us to survey expression at over 40,000 genes and to identify the contributions to expression in the polyploid from each of the two homoeologous copies contributed by its diploid progenitors. Different suites of genes are up-regulated under light-stress conditions in all three species, with the polyploid showing slightly higher expression than midparent predictions. Contact : Jeffrey J. Doyle