The role of volatile organic compounds, morphology and pigments of globeflowers in the attraction of their specific pollinating flies.

13 pagesInternational audienceFloral scents and visual cues of the globeflower Trollius europaeus may play a key role in the attraction of Chiastocheta flies, involved in a highly specific nursery pollination mutualism.Here, headspace collection and GC-MS were used to identify and quantify the volatile organic compounds emitted by the globeflower.Scents are produced in three different floral parts by four structures: secretory glands and flat epidermis cells in the abaxial sepal epidermis, conical cells in the adaxial sepal epidermis, and pollen. The blend is made up of 16 compounds commonly found in floral scents. Geographical variation among populations is low compared with variation amongst individuals within populations. Electroantenno-graphic analyses revealed that six compounds emitted by both anthers and sepals are detected by Chiastocheta flies. Removing the anthers hidden inside the globe from flowers in the field decreased the number of fly visits to globeflowers.A multivariate analysis of the effect of several floral traits on pollinator visitation rate conducted in the field showed that both floral scents and visual flower cues play a role in pollinator attraction. However, their relative roles and the intensity of the selective pressures exerted on floral traits by pollinators appear to vary in time and space

Micropropagation of Gerbera

International audienc

Production and Emission of Volatile Compounds by Petal Cells

We localized the tissues and cells that contribute to scent biosynthesis in scented and non-scented Rosa × hybrida cultivars as part of a detailed cytological analysis of the rose petal. Adaxial petal epidermal cells have a typical conical, papillate shape whereas abaxial petal epidermal cells are flat. Using two different techniques, solid/liquid phase extraction and headspace collection of volatiles, we showed that, in roses, both epidermal layers are capable of producing and emitting scent volatiles, despite the different morphologies of the cells of these two tissues. Moreover, OOMT, an enzyme involved in scent molecule biosynthesis, was localized in both epidermal layers. These results are discussed in view of results found in others species such as Antirrhinum majus, where it has been shown that the adaxial epidermis is the preferential site of scent production and emission

Production and Emission of Volatile Compounds by Petal Cells

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Towards the rose genome sequence and its use in research and breeding

Rose is one of the most economically important ornamental crops worldwide. Rosa sp. can become a model for woody ornamentals. Its genome size is relatively small (560 Mb), its genetic history with ploïdy events is well documented, and rose has a short life for a woody plant. Furthermore, different tools are available, including transcriptomic tools, genetic maps and genetic transformation protocols. Rose represents an original model for studying some ornamental traits that cannot be addressed in other model plant species such as Arabidopsis. Some of these traits, such recurrent blooming, flower morphogenesis or scent production and emission, are of economic interest. Different groups involved in rose genetics and genomics gathered to form the ‘Rose Genome Sequence Initiative’. Our objective is to obtain a high quality rose genome sequence of the diploid R. chinensis ‘Old Blush’. One important issue is the high level of heterozygosity of roses. To tackle this issue, different strategies are proposed: production of a haploid and development a high density genetic map to anchor the genome. This genetic map will be developed from a cross between ‘Old Blush’ and R. wichurana. The genotype R. chinensis ‘Old Blush’ will be sequenced using NGS technologies. The data will be assembled and arranged using the high-density map. In order to increase ESTs and to facilitate genome annotation, we have recently produced ESTs from various tissues of ‘Old Blush’ under different conditions. Digital expression (RNA Seq) was obtained from the different tissues and data are available on the following web site (https:// iant.toulouse.inra.fr/plants/rosa/FATAL/). The rose genome sequence will be a great step to help identifying the molecular basis of ornamental traits and also to study genetic diversity and genome evolution in the genus Rosa and in the Rosaceae famil

Parfum de rose

International audienc

Towards the Rose Genome Sequence and Its Use in Research and Breeding

International audienceRose is one of the most economically important ornamental crops worldwide. Rosa sp. can become a model for woody ornamentals. Its genome size is relatively small (560 Mb), its genetic history with ploidy events is well documented, and rose has a short life for a woody plant. Furthermore, different tools are available, including transcriptomic tools, genetic maps and genetic transformation protocols. Rose represents an original model for studying some ornamental traits that cannot be addressed in other model plant species such as Arabidopsis. Some of these traits, such recurrent blooming, flower morphogenesis or scent production and emission, are of economic interest. Different groups involved in rose genetics and genomics gathered to form the 'Rose Genome Sequence Initiative'. Our objective is to obtain a high quality rose genome sequence of the diploid R. chinensis 'Old Blush'. One important issue is the high level of heterozygosity of roses. To tackle this issue, different strategies are proposed: production of a haploid and development a high density genetic map to anchor the genome. This genetic map will be developed from a cross between 'Old Blush' and R. wichurana. The genotype R. chinensis 'Old Blush' will be sequenced using NGS technologies. The data will be assembled and arranged using the high-density map. In order to increase ESTs and to facilitate genome annotation, we have recently produced ESTs from various tissues of 'Old Blush' under different conditions. Digital expression (RNA Seq) was obtained from the different tissues and data are available on the following web site (https://iant.toulouse.inra.fr/plants/rosa/FATAL/). The rose genome sequence will be a great step to help identifying the molecular basis of ornamental traits and also to study genetic diversity and genome evolution in the genus Rosa and in the Rosaceae family