Modern roses arise from the hybridisation of European roses with Chinese roses, the arrival of which in Europe at the end of the 18th century considerably boosted the breeding of varieties.  Indeed, Chinese roses differed from European roses in terms of their ability to flower perpetually from the spring to the autumn.  In addition, Chinese roses were characterised by their scent, containing high levels of phenolic compounds such as dimethoxytoluene (DMT), the subtle fragrance of which is reminiscent of tea.  During the 1860s, the creation of new varieties led to modern, perpetually flowering "hybrid tea" roses, the name coming from their DMT-rich scent inherited from Chinese roses.  Hybrid tea roses have since seen considerable success and became the most widely-planted garden roses during the 20^th century.

Analysis of the mechanism of DMT formation has made it possible to understand the evolutionary origin of this tea scent.  Indeed, the later stages of biosynthesis of this compound requires the successive action of two very similar enzymes, coded by the OOMT1 and OOMT2 genes.

The scientists characterised the OOMT genes in 18 species of wild roses representative of the Rosa genus.  Their work showed that although all the roses possessed the OMT2 gene, only Chinese roses also had the OOMT1 gene.  Furthermore, phylogenetic analysis of this gene family revealed that the OOMT1 gene in Chinese roses had evolved from a duplication of the OOMT2 gene, particularly thanks to a point mutation modifying the active site of the corresponding OOMT1 enzyme.  This characteristic mutation of the OOMT1 gene gave rise to a much more effective enzyme which, added to OOMT2, enabled the efficient synthesis of DMT.
The OOMT1 gene and the tea scent, originally limited to two species of wild Chinese roses, were transmitted during the breeding process of modern roses and are today found in thousands of the cultivars present in gardens throughout the world. 
Although many garden roses are scented, the same does not apply to recent varieties created for the cut flower market.  Indeed, these varieties have  been bred for their yield and vase life, and are often devoid of scent.  In recent years, however, scent has once again become a trait of interest to consumers, and is playing an increasingly important role in the commercial success of new varieties, although scent is characterised by a complex heritability which makes it particularly difficult to take into account in present-day breeding plans.  This study forms part of international research efforts aimed at better understanding the mechanisms underlying scent production in roses, so as to achieve better control over this complex trait.