Genetics and genomics of prickle in roses

Rose is the most important ornamental plant in the world and an interestingmodel to study the genetic basis of original ornamental traits such as scent production,seasonality of blooming or the presence of prickles. Our objective is to decipher themolecular control of ornamental traits in rose by combining genetic and genomicapproaches. I will present here the last results we obtained concerning prickledevelopment. In rose, two types of prickles are present: non-glandular (NGP) andglandular (GP) prickles. Prickles (NGP or GP) are originated from cells below theprotoderm clearly demonstrating that they correspond to prickles and not trichomes.Four QTLs controlling the presence and density of prickles were identified. Bycomparing the transcriptome of glabrous and prickle shoots, we identified keyregulators and interestingly demonstrated that homologous genes, which known to beinvolved in trichome initiation and development, were not involved in prickle initiationand development. These results suggest a unique developmental pathway for pricklesin rose. All these results contribute i) to well understand the genetic determinism ofornamental traits, ii) to develop tools to help breeding, and iii) to eventually betterunderstand the rose domestication