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International audience; Conditioned both by environment, genotype and the interaction of the genotype itself with the environment, some phenotypic plasticity lies between individuals. This phenomenon allows an adaptive potential of individuals, and may depend on various mechanisms as overdominance, epistasis, pleiotropy, gene linkage and epigenetics. Depending on studied characters, some genotypes or cultivars may be more and less plastic and, in some cases, more and less stable. Considered as powerful anti-oxidants, carotenoids have large applications in medical fields as cancer preventive compounds and precursors of vitamin A and there is an interest for guaranteed carotenoid content in crops. Even if carotenoid accumulation seems to depend on a high genetic component for climacteric fruits as tomato, there is a large effect of G×E interaction overall. Thus, the genetic determinism alone does not explain carotenoid accumulation among most vegetables. Carrot is depicted as a healthy vegetable, thanks to its ability to accumulate carotenoids at high level in roots. However a large variation is observed. In spite of a well-known carotenoid biosynthesis pathway and recent progress on the genetic control, carotenoid accumulation in an underground reserve tissue remains unclear. Regulation can occur at several scales and can result from environmental influences. This article deals with the implication of genotype by environment interaction on carotenoid accumulation and the underlying mechanisms.

24 Páginas Daucus has traditionally been estimated to comprise 21–25 species, but a recent study expanded the genus to c. 40 species. The present study uses ten nuclear orthologues to examine 125 accessions, including 40 collections of 11 species (D. annuus, D. arcanus, D. decipiens, D. durieua, D. edulis, D. gracilis, D. minusculus, D. montanus, D. pumilus, D. setifolius and D. tenuissimus) newly examined with nuclear orthologues. As in previous nuclear orthologue studies, Daucus resolves into two well-defined clades, and groups different accessions of species together. Maximum likelihood and maximum parsimony analyses provide concordant results, but SVD quartets reveals many areas of disagreement of species within these two major clades. With maximum likelihood and maximum parsimony analyses Daucus montanus (hexaploid) is resolved as an allopolyploid between D. pusillus (diploid) and D. glochidiatus (tetraploid), whereas with SVD quartets it is resolved as an allopolyploid between D. glochidiatus and an unknown Daucus sp. We propose the new combination Daucus junceus (Durieua juncea) for a neglected species endemic to the south-western Iberian Peninsula often referred to as D. setifolius, and we place D. arcanus in synonymy with D. pusillus. Three lectotypes are also designated. INTRODUCTION. MATERIAL AND METHODS. RESULTS. DISCUSSION. NOMENCLATURAL PROPOSALS. REFERENCES

International audience; Epidemiological studies have shown that carrot consumption may be associated with a lower risk of developing several metabolic dysfunctions. Our group previously determined that the Bolero (Bo) carrot variety exhibited vascular and hepatic tropism using cellular models of cardiometabolic diseases. The present study evaluated the potential metabolic and cardiovascular protective effect of Bo, grown under two conditions (standard and biotic stress conditions (BoBS)), in apolipoprotein E-knockout (ApoE−/−) mice fed with high fat diet (HFD). Effects on metabolic/hemodynamic parameters and on atherosclerotic lesions have been assessed. Both Bo and BoBS decreased plasma triglyceride and expression levels of genes implicated in hepatic de novo lipogenesis and lipid oxidation. BoBS supplementation decreased body weight gain, secretion of very-low-density lipoprotein, and increased cecal propionate content. Interestingly, Bo and BoBS supplementation improved hemodynamic parameters by decreasing systolic, diastolic, and mean blood pressure. Moreover, Bo improved cardiac output. Finally, Bo and BoBS substantially reduced the aortic root lesion area. These results showed that Bo and BoBS enriched diets corrected most of the metabolic and cardiovascular disorders in an atherosclerosis-prone genetic mouse model and may therefore represent an interesting nutritional approach for the prevention of cardiovascular diseases.

International audience; Renewed consumer demand motivates the nutritional and sensory quality improvement of fruits and vegetables. Specialized metabolites being largely involved in nutritional and sensory quality of carrot, a better knowledge of their phenotypic variability is required. A metabolomic approach was used to evaluate phenotypic plasticity level of carrot commercial varieties, over three years and a wide range of cropping environments spread over several geographical areas in France. Seven groups of metabolites have been quantified by HPLC or GC methods: sugars, carotenoids, terpenes, phenolic compounds, phenylpropanoids and polyacetylenes. A large variation in root metabolic profiles was observed, in relation with environment, variety and variety by environment interaction effects in decreasing order of importance. Our results show a clear diversity structuration based on metabolite content. Polyacetylenes, beta-pinene and alpha-carotene were identified mostly as relatively stable varietal markers, exhibiting static stability. Nevertheless, environment effect was substantial for a large part of carrot metabolic profile and various levels of phenotypic plasticity were observed depending on metabolites and varieties. A strong difference of environmental sensitivity between varieties was observed for several compounds, particularly myristicin, 6MM and D-germacrene, known to be involved in responses to biotic and abiotic stress. This work provides useful information about plasticity in the perspective of carrot breeding and production. A balance between constitutive content and environmental sensitivity for key metabolites should be reached for quality improvement in carrot and other vegetables.

International audience

This book covers the scientific basis of biology and production of carrots and related Apiaceae crops, with updated technical crop management content. This new edition is divided intro three sections: (i) crops' importance and main features; (ii) carrots, from their genetic diversity and breeding to cropping systems, pests and disease management, quality, postharvest and valorization; and (iii) main aspects of 13 other cultivated Apiaceae. This book also highlights both unique and shared characteristics among Apiaceae species, describes the links between scientific principles and cropping systems and explores the relationship between crop management and product quality. Root quality, organic production and consumer expectations are also covered.

This chapter provides information on the domestication and evolution, genetic diversity and types of carrots (Daucus carota). The importance of carrot wild relatives for studies on evolutionary genetics, breeding, genetic improvement and taxonomy are also discussed.

Tuberous-rooted chervil, Chaerophyllum bulbosum, has been collected in the wild and used as a food since antiquity. The crop was first described in Austria in 1601. After realizing success as a crop during the 19th and beginning of the 20th centuries, particularly in France and Germany, it was forgotten by growers until the beginning of the last decade. This chapter discusses the importance, growing areas, plant development, cropping system (including soil preparation, sowing, irrigation and fertilizer (N, P and K) requirements, pest and disease management, and harvesting), postharvest storage and product quality of tuberous-rooted chervil.

Several disorders mainly of abiotic origin can occur on carrots, causing problems of varying degrees for producers. They are often responses to lack or excess of essential crop nutrients, light, moisture or temperature. Other factors may be poor soil structure, poor aeration, soil compaction, high soil salinity, air pollution or from chemical pesticides. Symptoms of these abiotic factors often are difficult to diagnose. Additional identification may be needed because some disorders mimic symptoms caused by viruses or other pathogens. This chapter describes carrot physiological disorders related to (i) root morphology and appearance, and (ii) plant development. Mechanisms of carrot adaptation to stress and various effects of main stresses (such as water stress, salinity, heavy metals and mechanical stress) are discussed.

—The genus Daucus is widely distributed worldwide, but with a concentration of diversity in the Mediterranean Region. The D. carota complex presents the greatest taxonomic problems in the genus. We focus on a distinctive phenotypic group of coastal morphotypes of D. carota, strictly confined to the margins to within about 0.5 km of the Mediterranean Sea and the Atlantic Ocean, which we here refer to as coastal morphotypes or D. carota subsp. “gummifer” complex. They are loosely morphologically coherent, sharing a relatively short stature, thick, broad, sometimes highly glossy leaf segments, and usually flat or convex fruiting umbels. We analyzed 288 accessions obtained from genebanks in England, France, and the USA, and an expedition to Spain in 2016, covering the Mediterranean and Atlantic coasts and Balearic Islands, where much of the gummifer complex variation occurs. Our study includes 112 accessions not examined before in this context. Genotyping-by-sequencing identified 29,041 filtered SNPs. Based on high bootstrap support from maximum likelihood and Structure analysis we highlight three main clades. The gummifer morphotypes are intercalated with members of Daucus carota subspecies carota and subspecies maximus in two of these main clades, including a clade containing accessions from Tunisia (also including D. carota subsp. capillifolius) and a clade containing accessions from western Europe (including the British Isles), southern Europe (including the Balearic Islands and the Iberian Peninsula) and Morocco. These results support five independent selections of the gummifer morphotypes in these restricted maritime environments in the Mediterranean and nearby Atlantic coasts. Daucus annuus (=Tornabenea annua) and Daucus tenuissimus (=Tornabenea tenuissima) also fall firmly within D. carota, supporting their classification as morphologically well-defined subspecies of D. carota, which are accepted here under the new combinations Daucus carota subsp. annuus and D. carota subsp. tenuissimus, respectively. Types are indicated for most of treated names, including designation of four lectotypes and three epitypes, which fix their further use.

Carrot is considered a healthy vegetable as it is rich in fibre and antioxidant-related compounds and with a low level of kilocalories. Some compounds are involved in both the nutritional and sensory quality. In most cases, carrot quality is highly dependent on the variety. However, environment conditions and growing practices influence carrot composition significantly. Whether for breeding for product quality or for producing carrots with high and stable quality, such influence needs to be better understood and taken into account. This chapter discusses the determinants of carrot quality, focusing on the influence of growing environment (such as area and year of production, sowing date and crop cycle, temperature and soil nature), growing practices (e.g. soil preparation, application of nitrogen, water supply, cover crops and growth stimulators), and cropping systems (conventional and organic). The effects of various stresses, such as water, temperature, salinity, cold, hail and Alternaria dauci infection, on carrot root composition and sensory perception are also discussed.

La question de l’agriculture urbaine et périurbaine (AUP) est aujourd’hui d’actualité en Tunisie parce qu’elle devient une préoccupation des politiques territoriales et des stratégies agri-urbaines en termes de gestion et de durabilité des milieux. Mais cette thématique multidisciplinaire présente encore des imprécisions et des tautologies dans les terminologies et dans l’acceptabilité de ce champ de production hybride agricole et urbain. C’est dans ce contexte que ce travail est entrepris pour cerner la vision de l’AUP par les acteurs publics, parapublics et privés. Les enquêtes menées directement (en face à face) auprès d’une population représentative de 85 acteurs révèlent un dualisme caractérisé à la fois par une « distanciation » et une « non distanciation » dans les différentes qualifications de l’AUP. La tendance montre plutôt une crise dans sa professionnalisation et dans sa visibilité, toutes deux réduites. Cependant, l’ensemble des populations enquêtées converge vers l’affirmation de l’intérêt de l’AUP, dans une vision limitée au productivisme de l’agriculture. Pour 58 % des acteurs publics, l’AUP est utile, mais plutôt dans une vision de production agricole résiduelle ; 30 % des acteurs publics la considèrent plutôt comme étant une activité en transition, de latence, de stock, ou de réserve foncière. Les acteurs parapublics présentent un ancrage dans les dimensions socio-spatiales, et ce, dans une logique agri-paysagère environnementaliste. Cette qualification est identifiée chez les trois quarts des acteurs parapublics et chez 50 % des acteurs publics. Une toute autre qualification est exprimée par les acteurs privés, plutôt tenants d’un urbanisme vert, car plus des deux tiers privilégient les services agroécologiques de médiation, les métiers verts et de l’obtention de produits agricoles de qualité et de proximité.

Urban agriculture (UA) is expanding in European cities and it has recently colonized the roof of buildings in the form of rooftop agriculture (RA), particularly due to urban land constraints. The implementation of RA has been done in multiple ways: from high-tech business-oriented solutions, often promoted by research and innovation programs of the European Commission, to agro-ecological and socially oriented initiatives lead by the citizenship. This paper evaluates the current state of RA implementation in Western Europe by reviewing existing projects. A systematic search through internet, UA-related networks and societies was performed to list the existing projects around Europe. A total of 33 initiatives were evaluated, including projects (concept and planned), implemented cases and already closed experiences. Four categories of RA project were revealed in Western Europe: gardens, farms, engineering and landscape. The multi-functionality of RA implies a combination of objectives and benefits, namely food and non-food production, economic and social services, financial and environmental impacts. The analysis also unveiled some implementation barriers that constrain the development of RA, limiting the long-term viability of existing projects. How many will remain in 5 years' time? And how many will replace them, and find a sustainable system? This is the role of research teams to study these initiatives, to test technical options and policy regulations through socioeconomic models and scenarios to offer an enabling environment for RA to become one way for cities to cope with climate change, food and nutrition security, biodiversity management and human prosperity.

National audience; Carotenoids are a large class of plant metabolites with a function of either essential nutrients or health promoting compounds for humans. Carrot root is a well-known and significant source of dietary carotenoids, mainly: alpha- and beta-carotene, lutein and lycopene. These pigments are the main carotenoids separated and quantified routinely by HPLC analysis. However, little is known about minor carotenoids, carotenoid esters and the carotenoids present in leaves despite their potential interest in metabolic and physiological studies. Previous works used C-18 columns but these stationary phases provide a poor resolution of structurally similar compounds and geometrical isomers. In recent years, C-30 columns have been developed and successfully applied at the separation of carotenoids from various plant materials, the number of resolved carotenoids being significantly improved. Based on literature procedures, we have developed a HPLC-DAD method with a C-30 column, adapted to the quantification of carotenoid compounds from carrot roots and leaves. A simple and rapid extraction method was optimized for both these types of samples on a panel of 5 genotypes displaying distinct root colours (different carotenoid composition and contents). Carotenoids from roots were separated in 23 minutes while carotenoids and chlorophylls from leaves were separated in 42 minutes. Compounds were identified according to their retention time and UV-visible spectrum in comparison with authentic standards (analysed individually and in combination, in the same conditions), or with data from literature, when standards were unavailable. Results showed that carrot root exhibited a simple profile with only 1 to 3 main carotenoids whereas a more complex composition was noticed in leaves, containing both identified and unidentified carotenoids and chlorophylls. Moreover, the composition was quite conservative for leaves but depended on the genotype for roots.

International audience; Carotenoids are essential for photosynthesis, and they are the ultimate source of all dietary vitamin A. They account for the striking diversity of orange, yellow, and red carrot storage root color, and this likely contributes to the fact that carotenoids are the most extensively studied class of compounds in carrot, where their biosynthesis and accumulation have been evaluated across diverse genetic backgrounds and environments. Many genes in the 2-C-methyl-D-erythritol-4-phosphate pathway (MEP) and carotenoid biosynthetic pathways have been identified and characterized in carrot, and genes in those pathways are expressed in carrot roots of all colors, including white carrots which contain at most trace amounts of carotenoids. The active functioning of genes in the carotenoid pathway in carrot roots of all colors should be expected since pathway products serve as precursors for hormones important in plant development. 1-Deoxy-d-xylulose-5-phosphate synthase (DXS) in the MEP pathway and the phytoene synthase and lycopene β-cyclase (PSY, LCYB) genes in the carotenoid pathway provide some level of overall regulation or modulation of these respective pathways, and these genes are incrementally upregulated in carrots with higher carotenoid content but variation in their expression does not account for the diverse content and composition of carotenoids in different colors of carrots. In contrast, genetic polymorphism in the Y and Y2 genes accounts for much for the variation in carotenoids accumulated in white, yellow, and orange carrots, and with the sequencing of the carrot genome, the genetic basis for these genes is becoming revealed. A candidate for the Y gene, DCAR_032551, is not a member of either the MEP or carotenoid biosynthesis pathway but rather a regulator of photosystem development and carotenoid storage. A clear candidate for the Y2 gene has not been identified, but no carotenoid biosynthetic gene was found in the genomic region defined by fine mapping of Y2. The Or gene, which regulates chromoplast development in other crops, was also recently associated with the presence of carotenoids in carrot. The discovery of genes outside the carotenoid biosynthetic pathway that contributes to carotenoid colors of carrots is but one exciting consequence of sequencing the carrot genome.

International audience; The Daucus carota diversity in Corsica (France) was previously investigated both at the morphological and genetic levels (Reduron et al., 2017). As wild carrot is rich in essential oils and volatiles, phytochemical compounds might represent a valuable diversity descriptor. A phytochemical analysis was conducted across 25 populations belonging to different infraspecific taxa and originating from various sites of Corsica Island. The analyzed organs were ripe fruits, seedling roots and seedling leaves. Compounds were identified and quantified by gas chromatography/mass spectrometry. Biochemical results analyzed by Principal Component Analysis (PCA) bring into evidence 6 populations possessing a distinctive chemical profile

International audience; Genebanks and other ex situ collections have a significant role in the conservation, management and use of crop genetic diversity, including that of crop wild relatives. Efficient management and use depends on insight into the patterning and distribution of genetic diversity as well as obtaining baseline information on phenotypic characters and traits. Wild carrot (Daucus carota L.) is the closest wild relative of cultivated carrot (Daucus carota L. subsp. sativus (Hoffm.) Arcang.), and is a potential source of useful traits for crop improvement. There are over 900 accessions of D. carota described as wild in European genebanks, however associated phenotypic and genotypic characterization data are sparse. The influence of environment on phenotype is also not well understood in this taxon, meaning that it is difficult to ascertain how data collected at different locations can be compiled and collated. We present initial results of CarrotDiverse, a collaborative project in which wild D. carota accessions are undergoing detailed phenotypic and morphological characterization in parallel at three sites of varying latitude across Europe located in Portugal, France and Sweden. This will allow us to understand which traits are affected by environmental variables. Basic phenotypic information is being collected on a further 150 accessions. Furthermore, resistance screening to Alternaria species and polyacetylene profiling will be included in the evaluation. A Genotyping by Sequencing approach will be used to generate knowledge about genetic background and trait associations. The project will result in a significant data set which will facilitate the use of crop wild relatives in carrot breeding and improvement.

Carrot is an essential vegetable produced and consumed worldwide. If yield and resistance to pests and diseases are major production concerns and breeding traits, product quality becomes more and more an issue, driven by society evolution and consumer demand. Product quality includes visual, nutritional, sensory attributes. Only a few of quality criteria are studied but most are influenced by agro-environmental conditions and controlled by a complex genetic determinism, making difficult to valorize quality in production or select for in breeding programs. The present article covers the various quality attributes, addresses the issue of plasticity/adaptability of carrot cultivars and the influence environmental and stresses on product quality, presents the genetic basis of quality and the tools to facilitate quality measurements, in order to help master product quality both at breeding and production levels.

Association mapping becomes one of the major genetic methods used to understand genetic control of complex traits. This method allows the use of natural populations with high resolution thanks to ancestral recombinations. Resolution is given by linkage disequilibrium (LD) extend. But false positives can be detected when phenotypic traits are correlated with underlying population stratification at non-causal loci. Knowledge of population structure is then a preliminary step for association mapping studies. Here the population structure was investigated in cultivated carrot and the LD extend in the carotenoid isomerase gene, a key gene in the carotenoid biosynthesis pathway. An unexpected high LD for outcrossing species was found in this gene. Population stratification analysis confirmed the differentiation of the carrot germplasm in two clusters. The first one comprised European and American accessions, the second one Asian accessions. These are preliminary steps to perform association mapping studies to understand root carotenoid content in cultivated carrot.

UMR BFP - Equipe Metabolisme; International audience; Carotenoids are important secondary metabolites involved in plant photosynthesis, vegetable nutritional quality but also in metabolic prevention in human health. Carrot represents one of the most important carotenoid intakes and is a very interesting model to study carotenoid metabolism. Till now, the knowledge about the impact of stress on carotenoid accumulation is limited. The purpose of this work was to investigate the impact of abiotic and biotic stresses applied separately or in combination on carotenoid accumulation in carrot leaves and roots. Results showed that combined stress decreased dramatically carotenoid content in both organs. In roots, the decrease in carotenoid content could be mostly associated in carrot response to A. dauci infection. Moreover, carotenoid and sugar contents were highly correlated, which suggests that stored metabolites are directly or indirectly involved in plant response to pathogen infection. In leaves, in contrast to results observed in roots, stresses impact carotenoid content depending on the genotype and the year. Moreover, carotenoid content variations were correlated to chlorophyll contents suggesting that a common mechanism of regulation for photosynthetic biosynthesis pigment exists.

Communication (Communication avec actes dans un congrès); International audience; Carotenoids are important plant metabolites considered as beneficial for human health. Provided by fruits and vegetables, they are supposed to be implicated in preventing several chronic diseases. In plants, carotenoids play multiple roles as antioxidant molecules. In light-exposed organs, they also act as photosynthesis accessory pigments and pollinator or disseminator attractors. However, in underground organs, like tuber or root, their role is not clearly understood.Carrot is one of the most important sources of dietary carotenoids due to high content in root. Moreover, the large genetic diversity of this species makes it a suitable model to study carotenogenesis. This diversity results in a differential accumulation of carotenoids: mostly β-carotene, α-carotene, lycopene and lutein, leading to various root colors. Although the carotenoid biosynthetic pathway is well-characterized, basic knowledge of carotenogenesis regulation in roots is still lacking. It is generally considered that carotenoid biosynthesis may be controlled at distinct levels: allelic polymorphism, transcriptional regulation, chromoplast differentiation and root development. Previous works have been conducted to elucidate how those different regulation scales impact carotenoid accumulation in carrots. For instance, single nucleotide polymorphisms detected in carotenoid biosynthesis genes like PSY are correlated with root color. However, little is known about the other types of regulation in carrot. In relation with these intracellular mechanisms, external factors may affect carotenoid accumulation as demonstrated for other plant secondary metabolites.This presentation is an overview of the current knowledge about the regulation of carotenoid accumulation in carrot root and the remaining questions to be addressed.

In this chapter, selected cases of rooftop agriculture across the world will be presented, explaining their organisation, technical design and operation, their business model and main functions , lessons learned during establishment and operation, their productive and societal results and their policy relevance . The owner or manager of the rooftop garden or farm and an independent researcher were involved in documenting the cases, When selecting the cases, we tried to include examples of the various types of rooftop agriculture presented in previous chapters. We also sought to include cases from all continents. Accordingly, a comprehensive list of most relevant rooftop agriculture experience across the world is presented, following an alphabetical order by city. For each case, the names of main informants (case study representatives) are listed altogether with the name of the author that coordinated data collection.

The preservation of our genetic resources and production of high-quality seeds depends on their ability to remain viable and vigorous during storage. In a quantitative trait locus analysis on seed longevity in Medicago truncatula, we identified the bZIP transcription factor ABSCISIC ACID INSENSITIVE5 (ABI5). Characterization of Mt-abi5 insertion mutant seeds revealed that both the acquisition of longevity and dormancy were severely impaired. Using transcriptomes of developing Mt-abi5 seeds, we created a gene coexpression network and revealed ABI5 as a regulator of gene modules with functions related to raffinose family oligosaccharide (RFO) metabolism, late embryogenesis abundant (LEA) proteins, and photosynthesis-associated nuclear genes (PhANGs). Lower RFO contents in Mt-abi5 seeds were linked to the regulation of SEED IMBIBITION PROTEIN1. Proteomic analysis confirmed that a set of LEA polypeptides was reduced in mature Mt-abi5 seeds, whereas the absence of repression of PhANG in mature Mt-abi5 seeds was accompanied by chlorophyll and carotenoid retention. This resulted in a stress response in Mt-abi5 seeds, evident from an increase in alpha-tocopherol and upregulation of genes related to programmed cell death and protein folding. Characterization of abi5 mutants in a second legume species, pea (Pisum sativum), confirmed a role for ABI5 in the regulation of longevity, seed degreening, and RFO accumulation, identifying ABI5 as a prominent regulator of late seed maturation in legumes.

1432-2048;Perrin, Florent;Hartmann, Laura;Dubois-Laurent, Cecile;Welsch, Ralf;Huet, Sebastien;Hamama, Latifa;Briard, Mathilde;Peltier, Didier;Gagne, Severine;Geoffriau, Emmanuel;Journal Article;Germany;Planta. 2017 Apr;245(4):737-747. doi: 10.1007/s00425-016-2637-9. Epub 2016 Dec 20.; International audience; Main conclusion Variations in gene expression can partially explain the difference of carotenoid accumulation in secondary phloem and xylem of fleshy carrot roots. The carrot root is well divided into two different tissues separated by vascular cambium: the secondary phloem and xylem. The equilibrium between these two tissues represents an important issue for carrot quality, but the knowledge about the respective carotenoid accumulation is sparse. The aim of this work was (i) to investigate if variation in carotenoid biosynthesis gene expression could explain differences in carotenoid content in phloem and xylem tissues and (ii) to investigate if this regulation is differentially modulated in the respective tissues by water-restricted growing conditions. In this work, five carrot genotypes contrasting by their root color were studied in control and water-restricted conditions. Carotenoid content and the relative expression of 13 genes along the carotenoid biosynthesis pathway were measured in the respective tissues. Results showed that in orange genotypes and the purple one, carotenoid content was higher in phloem compared to xylem. For the red one, no differences were observed. Moreover, in control condition, variations in gene expression explained the different carotenoid accumulations in both tissues, while in water-restricted condition, no clear association between gene expression pattern and variations in carotenoid content could be detected except in orange-rooted genotypes. This work shows that the structural aspect of carrot root is more important for carotenoid accumulation in relation with gene expression levels than the consequences of expression changes upon water restriction.

International audience; Carotenoids are important secondary metabolites involved in plant growth and nutritional quality of vegetable crops. These pigments are highly accumulated in carrot root but the knowledge about the environmental factors on their accumulation is limited. The purpose of this work was to investigate the impact of environmental variations on carotenoid accumulation in carrot leaves and roots. In this work, carrots were grown during two contrasted periods to maximize bioclimatic differences. In leaves, carotenoid and chlorophyll contents were lower in the less favorable growing condition while relative contents were well conserved for all genotypes suggesting a common regulatory mechanism. The down-regulation of all genes under environmental constraints demonstrates that carotenoid accumulation is regulated at transcriptional level. In roots, the decrease in α-carotene and lutein contents was accompanied by an increase of β-carotene relative content. At transcriptional level, LCYB and ZEP expression increased while LCYE expression decreased in the less favorable condition, suggesting that carotenoid biosynthesis is switched toward the β-branch.

According to the history of the cultivated carrot, root colour can be considered as a structural factor of carrot germplasm. Therefore, molecular variations of carotenoid biosynthesis genes, these being involved in colour traits, represent a good putative source of polymorphism related to diversity structure. Seven candidate genes involved in the carotenoid biosynthesis pathway have been analysed from a sample of 48 individual plants, each one from a different cultivar of carrot (Daucus carota L. ssp. sativus). The cultivars were chosen to represent a large diversity and a wide range of root colour. A high single nucleotide polymorphism (SNP) frequency of 1 SNP per 22 bp (mean pi (sil) = 0.020) was found on average within these genes. The analysis of genetic structure from carotenoid biosynthesis gene sequences and 17 putatively neutral microsatellites showed moderate genetic differentiation between cultivars originating from the West and the East (F (ST) = 0.072), this being consistent with breeding history, but not previously evidenced by molecular tools. Surprisingly, carotenoid biosynthesis genes did not exhibit decay of LD (mean r (2) = 0.635) within the 700-1,000 bp analysed, even though a fast decay level of LD is expected in outcrossing species. The high level of intralocus LD found for carotenoid biosynthesis genes implies that candidate-gene association mapping for carrot root colour should be useful to validate gene function, but may be unable to identify precisely the causative variations involved in trait determinism. Finally this study affords the first molecular evidence of a genetic structure in cultivated carrot germplasm related to phylogeography.

Cet article a pour objectif de montrer l'intérêt d'aborder la question de la création de valeur dans une perspective inter-organisationnelle alors que la plupart des travaux s'attachent à appliquer à l'entreprise vue de manière isolée le cadre conceptuel de la chaîne de valeur. Pour ce faire, une étude empirique a été réalisée auprès de 45 organisations situées aux différents niveaux de quatre filières du secteur du végétal spécialisé. Les résultats obtenus suggèrent que l'appartenance à une filière est une source de création de valeur. Ils doivent toutefois être nuancés afin de tenir compte des spécificités des différents modes de production, de commercialisation et de distribution qui ont pu être observés.

Article de revue (Article scientifique dans une revue à comité de lecture); International audience; Accumulated in large amounts in carrot, carotenoids are an important product qualityattribute and therefore a major breeding trait. However, the knowledge of carotenoid accumulationgenetic control in this root vegetable is still limited. In order to identify the geneticvariants linked to this character, we performed an association mapping study with a candidategene approach.We developed an original unstructured population with a broad geneticbasis to avoid the pitfall of false positive detection due to population stratification. Wegenotyped 109 SNPs located in 17 candidate genes – mostly carotenoid biosynthesisgenes – on 380 individuals, and tested the association with carotenoid contents and colorcomponents. Total carotenoids and β-carotene contents were significantly associated withgenes zeaxanthin epoxydase (ZEP), phytoene desaturase (PDS) and carotenoid isomerase(CRTISO) while α-carotene was associated with CRTISO and plastid terminal oxidase(PTOX) genes. Color components were associated most significantly with ZEP. Our resultssuggest the involvement of the couple PDS/PTOX and ZEP in carotenoid accumulation, asthe result of the metabolic and catabolic activities respectively. This study brings new insightsin the understanding of the carotenoid pathway in non-photosynthetic organs.

Direct spectrophotometric determination of quercetin content in onions (Allium cepa L.) was investigated as a possible alternative to high-performance liquid chromatography (HPLC) analysis. Quercetin content in five onion varieties was monitored at 362 nm and quantified using simple spectrophotometric and HPLC methods. HPLC revealed that 3,4'-Qdg and 4'-Qmg comprised up to 93% of total flavonol content detected in the studied varieties. These major quercetin conjugates combined (3,4'-Qdg + 4'-Qmg) and total flavonol conjugates quantified by HPLC correlated closely with spectrophotometer values. Correlation coefficients were 0.96 (P < 0.0001) for 3,4'-Qdg + 4'-Qmg and 0.97 (P < 0.0001) for total flavonol conjugates in onion. Simple spectrophotometric procedure proved to be a valid, efficient, and cost-effective method for the quantification of total quercetin in onion. Chemical names used: quercetin-3,4'-O-diglucoside (3,4'-Qdg); quercetin-4'-O-glucoside (4'-Qmg).

National audience; If in France, genetic resources of cultivated carrot are well studied and preserved, the wild compartment of the species remains less known and underutilized, while there are many populations of wild carrot on the French territory. Several collecting missions were undertaken from 2009 to 2014 to identify and collect populations, particularly in coastal areas, in continental France and Corsica. More than a hundred populations were collected, with a good distribution throughout the territory, and twelve taxa were identified. The status of these taxa is variable, with some very common and others underrepresented or restricted to a given area. Morphological and molecular studies are developed in order to improve the knowledge of taxonomy and diversity. The work confirms the specific interest of some populations and the taxonomic separation into 2 subgroups (i.e. grouping of several subspecies): subgr. carota and subgr. gummifer in Daucus carota L. The study conducted with microsatellite markers showed a high genetic differentiation between populations and a geographical structure between Mediterranean and Atlantic populations. This study will allow developing a strategy for management of genetic resources and their valorisation in breeding.

International audience; The typically intense carotenoid accumulation in cultivated orange-rooted carrots (Daucus carota) is determined by a high protein abundance of the rate-limiting enzyme for carotenoid biosynthesis, phytoene synthase (PSY), as compared with white-rooted cultivars. However, in contrast to other carotenoid accumulating systems, orange carrots are characterized by unusually high levels of α-carotene in addition to β-carotene. We found similarly increased α-carotene levels in leaves of orange carrots compared with white-rooted cultivars. This has also been observed in the Arabidopsis thaliana lut5 mutant carrying a defective carotene hydroxylase CYP97A3 gene. In fact, overexpression of CYP97A3 in orange carrots restored leaf carotenoid patterns almost to those found in white-rooted cultivars and strongly reduced α-carotene levels in the roots. Unexpectedly, this was accompanied by a 30 to 50% reduction in total root carotenoids and correlated with reduced PSY protein levels while PSY expression was unchanged. This suggests a negative feedback emerging from carotenoid metabolites determining PSY protein levels and, thus, total carotenoid flux. Furthermore, we identified a deficient CYP97A3 allele containing a frame-shift insertion in orange carrots. Association mapping analysis using a large carrot population revealed a significant association of this polymorphism with both α-carotene content and the α-/β-carotene ratio and explained a large proportion of the observed variation in carrots.

To increase the germplasm necessary for varietal improvement of tuberous-rooted chervil, a food apiaceae of increasing importance, two successive surveys of wild populations were carried out in Germany, in the Rhine and the Weser River basins. These mainly riparian populations are likely to be shaped by changes in hydrographic networks that characterize their habitat. Molecular studies have shown a strong structuration between wild populations (GST∼32%), but did not reveal any structuring effect of the hydrographic network on diversity or any global phenomenon of genetic erosion. A discussion about the strategy for maintaining the diversity of this species on a long-term period is proposed.

To increase the germplasm necessary for varietal improvement of tuberous-rooted chervil, a food apiaceae of increasing importance, two successive surveys of wild populations were carried out in Germany, in the Rhine and the Weser River basins. These mainly riparian populations are likely to be shaped by changes in hydrographic networks that characterize their habitat. Molecular studies have shown a strong structuration between wild populations (G(ST) similar to 32 %), but did not reveal any structuring effect of the hydrographic network on diversity or any global phenomenon of genetic erosion. A discussion about the strategy for maintaining the diversity of this species on a long-term period is proposed.; Afin d’accroître le pool génétique nécessaire à l’amélioration variétale du cerfeuil tubéreux, apiacée alimentaire en pleine expansion, des prospections de populations sauvages sur deux campagnes successives ont été réalisées dans les bassins du Rhin et de la Weser, en Allemagne. Ces populations, principalement ripariennes, sont susceptibles d’être façonnées par les évolutions des réseaux hydrographiques qui caractérisent leur biotope. L’étude moléculaire de la diversité génétique des populations montre une structuration forte entre ces populations sauvages (GST ∼ 32 %), mais ne met pas en évidence d’effet structurant des réseaux hydrographiques sur cette diversité, ni de phénomène d’érosion génétique global. Une discussion sur la stratégie de maintien de la diversité de cette espèce à long terme est proposée.

Communication (Communication avec actes dans un congrès); International audience; Orange carrots are the example par excellence for extraordinary high and stable accumulation of carotenoids. In contrast to other carotenoid-accumulating systems, knowledge on the molecular mechanisms involved is rather sparse. The first enzyme of the carotenoid pathway, phytoene synthase (PSY), frequently determines carotenoid amounts in many other tissues, and we thus investigated its contribution to carotenoid accumulation in carrots. Overexpression of PSY in white-rooted carrots resulted in the accumulation of b-carotene as crystals. This confirmed that increased phytoene synthesis is sufficient to achieve b-carotene concentrations high enough to result in the formation of crystals. In agreement with this, PSY protein amounts were high in orange but almost absent in white-rooted carrot cultivars. However, this contrasted with only slightly different PSY expression levels comparing white and orange carrots and suggests additional mechanisms acting beyond transcription. In fact, we found a negative feedback regulation emerging from xanthophyll-derived metabolites which modulate PSY protein levels. This was shown by the overexpression of the carotene hydroxylase CYP97A3 from Arabidopsis in orange carrots. These lines showed strongly reduced a-carotene levels through its enhanced CYP97A3-catalyzed hydroxylation, but also lower PSY protein levels which accordingly resulted in lower total carotenoid amounts. In agreement with these findings, we identified an 8 nt frame shift insertion in a carrot CYP97A3 hydroxylase allele encoding a truncated and thus non-functional enzyme. The corresponding polymorphism was significantly associated with high a-carotene levels and high a-/b-carotene ratios determined in a large association mapping analysis and explained a large proportion of the variation in carrots. Our results emphasize the rate-limiting role for PSY in carotenoid biosynthesis and show that previously unknown regulatory mechanisms determine carotenoid accumulation in orange carrots.

Polyacrylamide gel electrophoresis (PAGE) was used to study the polymorphism of esterases in Allium cepa L. and A. fistulosum L. Two varieties of each species, an A. fistulosum × A. cepa interspecific F1 hybrid, and (A. fistulosum × A. cepa) hybrid derivatives were analyzed for determination of banding patterns upon staining with α- and β-napthyl acetate substrates of esterase. Complex band patterns were observed. In total, 10 bands were detected between A. cepa and A. fistulosum — five inA. cepa, six in A. fistulosum with only one band common to both species. With the exception of one band unique to A. fistulosum which appeared only when stained with α-substrate, extracts of both A. cepa and A. fistulosum leaf tissue exhibited the same bands when stained with both α- and β-substrates. Bands stained with the different systems are distinguished by color: α-substrate always appeared black, while bands stained to β-substrate are always red. Esterase bands were assigned into 5 presumptive loci of four zones of activity with according to the migration distance of the bands from the front, color of each band upon staining with α- and β-substrates, and segregation observed in crosses and hybrid derivatives. Esterase enzymes detected in this study appear to be monomeric. Polymorphisms were identified between A. cepa and A. fistulosum by esterase banding patterns. Esterase enzymes provide an additional marker in monitoring introgression of foreign germplasm in interspecific onion breeding.

Onion varieties from Northern-Europe, Eastern-Europe, Southern-Europe and the U.S. including populations, inbreds, synthetics and clones were tested for their gynogenesis ability for three years: 1993-1995. Embryos were induced in Petri dishes using in vitro culture of flower buds. Embryo rate, regeneration rate, survival rate, embryo quality and ploidy level of regenerants are described. Important genotype and variety effects are pointed out; embryo production and plant regeneration ranged from 0 to 17% and from 0 to 11% of inoculated flowers, respectively. Highest results were obtained with inbreds and synthetics for embryo production as well as for plant regeneration. Populations expressed various responses which were generally low. Geographic origin and year effects were covered by the effects of genetic structure of varieties and specific genotype of donor plant. Among regenerants, 80% were haploid and 13% were spontaneous diploid. No relation has been found between general quality and ploidy level of regenerants. The choice of plant material for successful gynogenesis in onion is discussed.

Carrot is one of the major vegetables, and is a basic product highly valued by regular buyers. In spite of the natural resources of the species, diversity for consumers is poor. The aim of this work was to identify consumer preferences based on appreciation of batches representative of the carrot sensory space. Ten batches were described by a trained panel using a list of 10 attributes. The same products were given to a panel of 299 consumers from 3 French cities (Avignon, Angers, and Paris). They gave a score of general appreciation and answered a questionnaire about usage and attitude. The results show that carrots are mainly characterized by the perception of bitterness, pungency and chemical flavor in opposition to the perception of sweetness. Some batches had a higher level for global aroma. Other batches were characterized by juiciness as opposed to a high level of firmness and retention in the mouth. The highest levels of consumer satisfaction were achieved with flavored, juicy and sweet carrots. Main rejected characteristics were too much bitterness and too intense chemical flavor. The segmentation study identified three groups of consumers, differing mainly by their attitude towards the product. A group representing 20% of the panel was characterized by very marked preferences for sweet and flavored products and also for interest in a high quality product.