S05 - Session O6 - Keynote: Towards reclassification of the genus Rosa

Authors: Valéry Malecot *, Kevin Debray

The genus Rosa consists in about 150 to 200 species and more than 30 000 cultivars. Widely known for its ornamental and perfumery usages, this genus is the subject of two classificatory systems, one for wild taxa, the second one for cultivated ones. If the classification of cultivated roses is relatively recent, being the result of negotiations within WFRS, the classification for wild roses mainly relies on an updated version of Rehder's classification published in the 1940's. From Rehder's classification, it is also easy to track down to Lindley's classification published in 1820. Since these dates, procedures and assumptions underlying botanical classification changed. Molecular data such as RAPD, ISSR, ITS sequences, have been used to try to revise classification of the genus Rosa but without success up to now. Here we show how the availability of the Rosa 'Old Blush' full genome sequence, access to genome of several species, and selection of nuclear genes, provide an unprecedent way to classify wild roses. In addition, because of numerous events of genome duplication or polyploidization, and interspecific hybridizations followed by speciation, new methodological approaches have been applied to this data. This allows us to present a revised evolutionary history of the genus and consequences of such history on the classification of the genus Rosa