The Rose Genome Sequencing Initiative, Prospects and Perspectives

Roses are of high symbolic value and have great cultural importance in different societies worldwide. The rose is well suited to be an original model organism for woody ornamental species as it has a relatively small genome size (560Mbp) and it has a short life cycle for a perennial woody plant. Several characters, such as recurrent blooming, flower morphogenesis, scent(1),… are of high economic importance. During the past years, we generated a number of molecular, genomic and biotechnology tools(2) such as efficient genetic transformation(3) and a database that provides useful information on Rosa expressed genes with thorough annotation and an overview of gene expression patterns with good accuracy(4) ; the latest represented a valuable prerequisite to the the rose genome sequencing. We have undertaken the genome sequencing of the diploid Rosa chinensis cv Old Blush, an an ancestor of modern roses that contributed several important characters. We generated and assembled a high quality genome sequence for this cultivar, but its relatively high heterozygosity hampered high quality genome assembly. To overcome this difficulty, we successfully generated a R. chinensis rose homozygous tissue (HzRc-RDP12) using Old Blush as starting material. The sequencing and assembly of this homozygous genotype is in progress. The availability of the rose genome sequence will be of great help for discovering the molecular and genetic mechanisms controlling many horticultural traits in Rosa sp. and likely in other ornamental species. (1)Magnard 2015 Science 349:81-3. (2)Bendahmane 2014 J Exp Bot 64:847-57. (3)Vergne 2010. PCTOC 100:73-81. (4)Dubois 2012 BMCGenomics 13:638.