Olivier Raymond

University of Lyon, Lyons, Rhône-Alpes, France

Are you Olivier Raymond?

Claim your profile

Publications (12)64.11 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Roses hold high symbolic value and great cultural importance in different societies throughout human history. They are widely used as garden ornamental plants, as cut flowers, and for the production of essential oils for the perfume and cosmetic industries. Domestication of roses has a long and complex history, and the rose species have been hybridized across vast geographic areas such as Europe, Asia, and the Middle East. The domestication processes selected several flower characters affecting floral quality, such as recurrent flowering, double flowers, petal colours, and fragrance. The molecular and genetic events that determine some of these flower characters cannot be studied using model species such as Arabidopsis thaliana, or at least only in a limited manner. In this review, we comment on the recent development of genetic, genomic, and transcriptomic tools for roses, and then focus on recent advances that have helped unravel the molecular mechanisms underlying several rose floral traits.
    Journal of Experimental Botany 01/2013; · 5.24 Impact Factor
  • Source
    Chapter: Rosa
    [Show abstract] [Hide abstract]
    ABSTRACT: Presently, about 100–250 species are usually recognized in the genus Rosa. The low levels of DNA sequence divergence found across the genus suggest that it is a young genus with much speciation taking place after the last glaciation. Poor phylogenetic resolution and commonly occurring contradictions between chloroplast and nuclear gene phylogenies suggest that hybridization has been a strong driving force in the evolution of roses, often accompanied by polyploidization. In addition, extensive anthropogenic impact has led to the development of many new semi-wild and/or cultivated rose varieties. Some wild species have become invasive. This chapter describes the taxonomy of roses. It presents examples of interesting traits in wild species that may valuable to broaden the genetic base of cultivated roses, such as thornlessness, winter hardiness, drought resistance, and improved shelf-life. Also fragrance and compounds with possible health effects are discussed. The highest priority in rose breeding research is the development of disease resistant roses. Different resistance mechanisms have been found for black spot and powdery mildew in various wild rose species. We describe how resistance genes are being mapped using crosses between wild, diploid rose species, and how other genes for traits of interest are being identified. We proceed with a discussion of various ways to overcome the taxonomic and ploidy level barriers for introgression of traits into cultivated hybrid rose or garden rose germplasm, including dihaploidization, polyploidization, and transgenics. Even so, breeding programs with wild species are usually time-consuming. For garden roses, the genetic and morphological distance between modern cultivars and the wild species is smaller, which makes the use of wild species easier than in the case of cut roses.
    08/2011: pages 243-275;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cultivated for centuries, the varieties of rose have been selected based on a number of flower traits. Understanding the genetic and molecular basis that contributes to these traits will impact on future improvements for this economically important ornamental plant. In this study, we used scanning electron microscopy and sections of meristems and flowers to establish a precise morphological calendar from early rose flower development stages to senescing flowers. Global gene expression was investigated from floral meristem initiation up to flower senescence in three rose genotypes exhibiting contrasted floral traits including continuous versus once flowering and simple versus double flower architecture, using a newly developed Affymetrix microarray (Rosa1_Affyarray) tool containing sequences representing 4765 unigenes expressed during flower development. Data analyses permitted the identification of genes associated with floral transition, floral organs initiation up to flower senescence. Quantitative real time PCR analyses validated the mRNA accumulation changes observed in microarray hybridizations for a selection of 24 genes expressed at either high or low levels. Our data describe the early flower development stages in Rosa sp, the production of a rose microarray and demonstrate its usefulness and reliability to study gene expression during extensive development phases, from the vegetative meristem to the senescent flower.
    PLoS ONE 01/2011; 6(12):e28455. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Roses have been cultivated for centuries and a number of varieties have been selected based on flower traits such as petal form, color, and number. Wild-type roses have five petals (simple flowers), whereas high numbers of petals (double flowers) are typical attributes of most of the cultivated roses. Here, we investigated the molecular mechanisms that could have been selected to control petal number in roses. We have analyzed the expression of several candidate genes known to be involved in floral organ identity determination in roses from similar genetic backgrounds but exhibiting contrasting petal numbers per flower. We show that the rose ortholog of AGAMOUS (RhAG) is differentially expressed in double flowers as compared to simple flowers. In situ hybridization experiments confirm the differential expression of RhAG and demonstrate that in the double-flower roses, the expression domain of RhAG is restricted toward the center of the flower. Conversely, in simple-flower roses, RhAG expression domain is wider. We further show that the border of RhAG expression domain is labile, which allows the selection of rose flowers with increased petal number. Double-flower roses were selected independently in the two major regions for domestication, China and the peri-Mediterranean areas. Comparison of RhAG expression in the wild-type ancestors of cultivated roses and their descendants both in the European and Chinese lineages corroborates the correlation between the degree of restriction of RhAG expression domain and the number of petals. Our data suggests that a restriction of RhAG expression domain is the basis for selection of double flowers in both the Chinese and peri-Mediterranean centers of domestication. We demonstrate that a shift in RhAG expression domain boundary occurred in rose hybrids, causing double-flower phenotype. This molecular event was selected independently during rose domestication in Europe/Middle East and in China.
    PLoS ONE 01/2010; 5(2):e9288. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The phenolic methyl ether 3,5-dimethoxytoluene (DMT) is a major scent compound of many modern rose varieties, and its fragrance participates in the characteristic "tea scent" that gave their name to Tea and Hybrid Tea roses. Among wild roses, phenolic methyl ether (PME) biosynthesis is restricted to Chinese rose species, but the progenitors of modern roses included both European and Chinese species (e.g., Rosa chinensis cv Old Blush), so this trait was transmitted to their hybrid progeny. The last steps of the biosynthetic pathways leading to DMT involve two methylation reactions catalyzed by the highly similar orcinol O-methyltransferases (OOMT) 1 and 2. OOMT1 and OOMT2 enzymes exhibit different substrate specificities that are consistent with their operating sequentially in DMT biosynthesis. Here, we show that these different substrate specificities are mostly due to a single amino acid polymorphism in the phenolic substrate binding site of OOMTs. An analysis of the OOMT gene family in 18 species representing the diversity of the genus Rosa indicated that only Chinese roses possess both the OOMT2 and the OOMT1 genes. In addition, we provide evidence that the Chinese-rose-specific OOMT1 genes most probably evolved from an OOMT2-like gene that has homologues in the genomes of all extant roses. We propose that the emergence of the OOMT1 gene may have been a critical step in the evolution of scent production in Chinese roses.
    Proceedings of the National Academy of Sciences 05/2008; 105(15):5927-32. · 9.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Much of our knowledge of speciation genetics stems from quantitative trait locus (QTL) studies. However, interpretations of the size and distribution of QTL underlying species differences are complicated by differences in the way QTL magnitudes are estimated. Also, many studies fail to exploit information about QTL directions or to compare inter- and intraspecific QTL variation. Here, we comprehensively analyze an extensive QTL data set for an interspecific backcross between two wild annual sunflowers, Helianthus annuus and H. petiolaris, interpret different estimates of QTL magnitudes, identify trait groups that have diverged through selection, and compare inter- and intraspecific QTL magnitudes. Our results indicate that even minor QTL (in terms of backcross variance) may be surprisingly large compared to levels of standing variation in the parental species or phenotypic differences between them. Morphological traits, particularly flower morphology, were more strongly or consistently selected than life history or physiological traits. Also, intraspecific QTL were generally smaller than interspecific ones, consistent with the prediction that larger QTL are more likely to spread to fixation across a subdivided population. Our results inform the genetics of species differences in Helianthus and suggest an approach for the simultaneous mapping of inter- and intraspecific QTL.
    Genetics 05/2005; 169(4):2225-39. · 4.39 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Diploid hybrid speciation in plants is often accompanied by rapid ecological divergence between incipient neospecies and their parental taxa. One plausible means by which novel adaptation in hybrid lineages may arise is transgressive segregation, that is, the generation of extreme phenotypes that exceed those of the parental lines. Early generation (BC2) hybrids between two wild, annual sunflowers, Helianthus annuus and Helianthus petiolaris, were used to study directional selection on transgressive characters associated with the origin of Helianthus paradoxus, a diploid hybrid species adapted to extremely saline marshes. The BC2 plants descended from a single F1 hybrid backcrossed toward H. petiolaris. The strength of selection on candidate adaptive traits in the interspecific BC2 was measured in natural H. paradoxus salt marsh habitat. Positive directional selection was detected for leaf succulence and Ca uptake, two traits that are known to be important in salt stress response in plants. Strong negative directional selection operated on uptake of Na and correlated elements. A significant decrease in trait correlations over time was observed in the BC2 population for Na and Ca content, suggesting an adaptive role for increased Ca uptake coupled with increased net exclusion of Na from leaves. Patterns of directional selection in BC2 hybrids were concordant with character expression in the natural hybrid species, H. paradoxus, transplanted into the wild. Moreover, the necessary variation for generating the H. paradoxus phenotype existed only in the BC2 population, but not in samples of the two parental species, H. annuus and H. petiolaris. These results are consistent with the hypothesis that transgressive segregation of elemental uptake and leaf succulence contributed to the origin of salt adaptation in the diploid hybrid species H. paradoxus.
    Evolution 10/2003; 57(9):1989-2000. · 4.86 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hybridization is frequent in many organismal groups, but its role in adaptation is poorly understood. In sunflowers, species found in the most extreme habitats are ancient hybrids, and new gene combinations generated by hybridization are speculated to have contributed to ecological divergence. This possibility was tested through phenotypic and genomic comparisons of ancient and synthetic hybrids. Most trait differences in ancient hybrids could be recreated by complementary gene action in synthetic hybrids and were favored by selection. The same combinations of parental chromosomal segments required to generate extreme phenotypes in synthetic hybrids also occurred in ancient hybrids. Thus, hybridization facilitated ecological divergence in sunflowers.
    Science 09/2003; 301(5637):1211-6. · 31.20 Impact Factor
  • 01/2003; 301:1211-1216.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Single- or low-copy nuclear sequences are now widely employed for phylogenetic reconstruction. In a new paper, Ferguson and Sang apply this approach to allotetraploid species of peonies Paeonia and document the first case of natural homoploid hybrid speciation between tetraploid taxa. This surprising finding could shed light on the relationship between the two main pathways of hybrid speciation: allopolyploidization and homoploid hybrid speciation. In addition, this work illustrates both the promise and uncertainty associated with the reconstruction of reticulate phylogenies using molecular tools.
    Trends in Ecology & Evolution. 01/2002;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The primary requirement for a new diploid species to arise via hybridization is ecological divergence from its parental species. Ecological divergence protects the nascent hybrid species from competition with its progenitor species and may contribute to reproductive isolation. However, the means by which hybridization might facilitate the necessary adaptive transitions are poorly understood. Here, we report the results of a glasshouse experiment in which 42 morphological and ecophysiological traits were measured in three hybrid sunflower species (Helianthus anomalus, Helianthus deserticola, and Helianthus paradoxus) and their parental species (Helianthus annuus and Helianthus petiolaris). A surprisingly high proportion of traits were extreme relative to the parental species (24%, 20%, and 39% of traits in H. anomalus, H. deserticola, and H. paradoxus, respectively). Most of the extreme traits have previously been reported in the literature as adaptations to dune (H. anomalus), high-desert (H. deserticola), or high-salt (H. paradoxus) habitats. We propose that hybridization has contributed to ecological divergence largely via the generation of extreme traits in segregating hybrids, a commonly observed phenomenon called "transgressive segregation."
    International Journal of Plant Sciences 01/2002; 163(3):387-398. · 1.54 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: ABSTRACT Much of our knowledge of speciation genetics stems from quantitative trait locus (QTL) studies. However, interpretations,of the size and,distribution of QTL underlying,species differences,are complicated,by differences in the way QTL magnitudes are estimated. Also, many studies fail to exploit information about QTL directions or to compare inter- and intraspecific QTL variation. Here, we comprehensively analyze an extensive QTL data set for an interspecific backcross between two wild annual sunflowers, Helianthus annuus and H. petiolaris, interpret different estimates of QTL magnitudes, identify trait groups that have diverged through selection, and compare inter- and intraspecific QTL magnitudes. Our results indicate that even,minor,QTL (in terms,of backcross,variance) may,be surprisingly large compared,to levels of standing variation in the parental species or phenotypic differences between them. Morphological traits, particularly flower morphology, were more strongly or consistently selected than life history or physiological traits. Also, intraspecific QTL were generally smaller than interspecific ones, consistent with the prediction that larger QTL are more,likely to spread,to fixation across a subdivided,population. Our results inform the genetics of species differences in Helianthus and,suggest an approach,for the simultaneous,mapping of inter- and,intraspecific QTL. R ECENT years have seen tremendous,conceptual,and,evidence,indicates that genes or QTL underlying,ordi-

Publication Stats

848 Citations
64.11 Total Impact Points

Institutions

  • 2011
    • University of Lyon
      Lyons, Rhône-Alpes, France
  • 2005
    • Royal Botanic Gardens, Kew
      • Jodrell Laboratory
      Richmond, ENG, United Kingdom
  • 2003
    • Indiana University Bloomington
      • Department of Biology
      Bloomington, IN, United States
  • 2002–2003
    • Claude Bernard University Lyon 1
      Villeurbanne, Rhône-Alpes, France