Résumé
Diversity and evolution of coffee trees in light of genomics
Coffee trees exhibit considerable diversity in terms of morphology, phenology and ecological adaptation. Several molecular studies have been undertaken in order to specify the evolutionary history of the coffee genome as well as the phylogeny and the diversification of the Coffea genus. The coffee tree species appear to result from a rapid and radial mode of speciation. Both a low sequence divergence and an almost perfect collinearity are observed between species. The gene expression regulatory mechanisms played a key role in the diversification and adaptive capacity of the coffee tree. Furthermore, comparative sequence analyses suggest that asterids (e.g. coffee trees) and rosids (e.g. grapevine) derive from the same paleo-hexaploid ancestral genome. No additional polyploidization events were detected in the Coffea lineage. This new knowledge on the coffee genome results in the possibility of improved strategies towards identifying and analysing agro-economically important genes, and should lead to a higher efficiency in plant breeding programmes.