Abstract

Roses, which are called the queen of flowers, are also the queen of fragrant flowers. Since ancient times, humans have been fascinated by the scent of roses, cultivated roses for use in perfumery, and enjoyed their scent.　An important species of rose for perfumery is R. × damascena (damask rose), whose scent is recognized as the typical rose scent.

Modern rose cultivars have a variety of scents, include a damask-like scent similar to the scent of damask roses, a fruity scent with a sour sweetness reminiscent of fruit, a black-tea-like scent and a spicy scent. These diverse rose scents are composed of many types of compounds classified as terpenoids, bensenoids/phenylpropanoids, etc. The main scent components of roses include the terpenoids citronellol, geraniol, geranyl acetate and nerol, and the bensenoids/phenylpropanoids 3,5-dimethoxytoluene, eugenol, 4-methoxystyrene, 2-phenylethanol and 2-phenylethyl acetate.

In this lecture, I will explain the main scent characteristics and scent components of roses that contributed to the birth of fragrant roses, from wild species (Rosa chinensis var. spontanea, R. gallica, R. gigantea, R. moschata and R. phoenicia) to old roses and modern roses. In addition, I discuss the scent components of R. foetida, which has an unpleasant scent, and ‘Anne-Marie de Montravel’, an early Polyantha cultivar that have like an old wooden-closet odor. Our research has recently revealed that the characteristic scent components of these roses are fatty acid derivatives. Much remains unknown about rose scents, and we expect that many new compounds will be discovered in our future study.

Biography

Dr. Naomi Okubo studies floral scent at Institute of Vegetable and Floriculture Science, NARO in Tsukuba. She received a Ph.D. in Agricultural Sciences for plant hormone research from the University of Tokyo in 1996. In 2001, National Institute of Floricultural Science (NIFS，now Institute of Vegetable and Floriculture Science, NARO), Japan’s first national institute specializing in flowers, was launched. She started her research on floral scent at NIFS.

So far, she has analyzed the scents of various flowers including lilies, tulips, petunias and camellias. For the past few years, she has been actively researching the scent of roses with Dr. Mikanagi.

Abstract

The recurrent-flowering behavior and double-flower morphology are both important traits for ornamental rose cultivars. The recurrent-flowering characteristic is believed to be originated from a mutant in a wild species in China, which was then introduced to Europe in the 18th century and became one of the essential traits for modern rose cultivars. The double-flower trait is considered to have multiple genetic origins, one of which is a retrotransposon-insertion mutation in AP2/TOE gene. The transposon-insertion mutation allows us to determine the nucleotide sequence of wild-type gene before the mutation by removing the transposon sequence. If we find a wild species that carry the same gene sequence as that of the wild type, we can assume that the wild species is the origin from which the mutation occurred. Using this approach, I have studied the wild origins of the recurrent-flowering and the double-flower mutations. The results suggest that the recurrent-flowering mutation originates from Rosa chinensis var. spontanea, as already reported by previous studies. In contrast, the double-flower mutation was found to most likely originate from a species in section Synstylae, which includes R. multiflora and R. brunonii, rather than in the section Chinenses, to which R. chinensis var. spontanea and R. odorata var. gigantea belong. This result supports the hypothesis that the old Chinese cultivars with recurrent-flowering and double-flower traits are of hybrid origin.

Biography

Dr. Koji Kawamura has studied roses from 2007 as he joined a project on genetic determinisms of garden rose architecture as a postdoc in French National Institute for Agriculture. His research area has then extended into (i) rose genome, (ii) genes controlling flowering behavior, self-incompatibility, and prickle formation, and (iii) an early domestication process of roses in China and Japan.

2011-present Associate Professor, Osaka Institute of Technology, Japan
2009-2011 Postdoc, Nagoya University, Japan
2007-2009 Postdoc, French National Institute for Agriculture, France
2005-2007 Postdoc, Forestry Forest Products Research Institute, Japan
2004 PhD. Agriculture, Kyoto University, Japan

Abstract

Rosa arvensis is a wild rose, largely distributed throughout temperate Europa, and one of the very few sciaphilous species. Rather understated during decades, the species has gained much interest in the last few years. Today, it appears into a position where it could have substantially influenced the evolution of other groups of roses during the explosive post-glacial European speciation. Besides evolutionary specificities, Rosa arvensis also sparks the interest of specialized metabolic pathways and health-beneficial molecules. The diploid statut of Rosa arvensis, raises the possibility to develop Rose genetics for a broad spectrum of biological events. The idea of bringing Rosa arvensis to a possible genetic model for roses, emerged in 1995. Several strands of knowledges were developed for this purpose. Efforts were being made to explore the intraspecific diversity. Spontaneous variants and mutants were sampled from large wild populations from most regions of France. Among this wild pool, a useful reference clone was chosen for genome sequencing and for an inbreeding program. For example, partial homozygous were achieved to facilitate the deciphering of rose genetics. Luckily, Rosa arvensis shows fine hybridity with both other species and cultivars. As a result of crosses, using the reference clone as the female parent and most heirloom cultivars as male parents, 60 half-sister sub-pedigrees were generated to dissect the genetics of the horticultural characteristics. Due to the lack of any consanguinity with cultivars, Rosa arvensis became ideal for this purpose. More than 200 characteristics were considered and classified, some of them being suitable for future breeding program. A new experimental Rosarium was built to preserve and study both the intraspecific biodiversity of Rosa arvensis and the new cultivar network, being recently awarded as a national French collection (CCVS). Hereby, I will share the results of a 30-year-old adventure.

Biography

Dr. Pascal Heitzler is geneticist at the University of Strasbourg, where he mainly worked on Drosophila neurogenesis. His experience in rose genetics nevertheless started in 1995. He is the holder of the French CCVS national collection of Rosa arvensis varieties. He built a unique network of pedigrees, own-bred roses representing 5 generations, to dissect formal genetics in roses, using Rosa arvensis as a model. He recently published a paper on the origin of the Bourbon roses, with a DNA-based reconstitution of the original founding pedigree.