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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.

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.

This chapter focuses on the various diseases affecting carrot production and their causal pathogens, such as Alternaria dauci, Xanthomonas hortorum pv. carotae, Cercospora carotae, Pythium spp., Sclerotinia spp., Rhizoctonia solani and Alternaria radicina, among others. Information on the symptoms of these diseases and the efficacy of various methods used in their control are also presented.

International audience; Carrot (Daucus carota ssp. sativus) production can be affected by a wide range of pests and pathogens. At least five diseases of carrot are caused by bacterial pathogens, 36 by fungal and oomycete pathogens, two by phytoplasmas, and 13 by viruses; and seven genera of nematodes and two genera of parasitic plants affect carrot. In addition, numerous insect and mite pests can cause losses. There have been extensive efforts to select carrot cultivars with partial or complete resistance to many of these pathogens and pests, and to identify wild species with resistance to specific biotic stresses for introgression into breeding populations and commercial cultivars. For some pathogens and pests, significant advances have been made at identifying resistance and mapping that resistance to the carrot genome. For others, resistance has been identified, but the genetic basis is yet to be determined. For a majority of these diverse stresses, however, there has been little success at identifying highly effective resistance and understanding the genetic basis of resistance. The diversity of stresses as well as interactions among these pests and pathogens can complicate efforts to develop cultivars with resistance to all key biotic stresses in a region that also meet market and consumer expectations. New approaches to identifying resistant material and speeding traditional breeding are being developed with molecular breeding tools, including simple sequence repeat markers and deep-coverage libraries of the carrot genome. These valuable genomic resources will enhance efforts to identify and breed for resistance to carrot pests and pathogens.

International audience; Developing carrot varieties highly resistant to Alternaria dauci is a top priority for breeders. Meanwhile , consumers are increasingly demanding as regards final product quality, particularly taste. Bitterness is one of the five common taste sensations, but it is rejected by most carrot consumers. Therefore, providing tools for efficient plant breeding of resistant, low bitter carrots would be helpful. While resistance QTLs (rQTLs) have already been identified for carrot resistance to A. dauci, the genetic control and mapping of the metabolites involved in bitterness perception have not been addressed so far. We identified the metabolites most involved in bitterness by combining chemical and sensory analyses of a set of resistant and susceptible carrot genotypes grown in different environments. We evaluated their genetic control and heritability in a segregating F 2:3 population over 2 years of field trials and searched for colocalizations between rQTLs and metab-olite QTLs (mQTLs) to evaluate the link between bitterness and resistance traits. Our results suggest that it is possible to increase resistance while favoring low bitter varieties by selecting genomic regions involved in the expression of one or the other trait and counter-selecting others when r-and mQTL colocalization is unfavorable.

Alternaria Leaf Blight (ALB), caused by the fungus Alternaria dauci, is the most damaging foliar disease affecting carrots (Daucus carota). In order to identify compounds potentially linked to the resistance to A. dauci, we have used a combination of targeted and non-targeted metabolomics to compare the leaf metabolome of four carrot genotypes with different resistance levels. Targeted analyses were focused on terpene volatiles, while total leaf methanolic extracts were subjected to non-targeted analyses using liquid chromatography couple to high-resolution mass spectrometry. Differences in the accumulation of major metabolites were highlighted among genotypes and some of these metabolites were identified as potentially involved in resistance or susceptibility. A bulk segregant analysis on F3 progenies obtained from a cross between one of the resistant genotypes and a susceptible one, confirmed or refuted the hypothesis that the metabolites differentially accumulated by these two parents could be linked to resistance.

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.

Small, finite populations are particularly vulnerable to diversity loss during regeneration. The regeneration of a highly outbreeding open-pollinated variety relies on estimated effective population size, via the measurement of temporal change in allele frequencies. Using appropriate estimators for dominant gene markers, effective sizes were calculated for five sizes of a mating population and two seed harvesting procedures. We have shown that, in the case of carrot regeneration, 70 equally harvested plants should provide an effective size (Ne) of at least 50 plants. This value seems sufficient to limit genetic drift and to preserve an efficient level of genetic diversity within the collection. The efficiency of balanced samples (made of an equal number of seeds per plant) is compared to that of bulk samples (seeds randomly chosen among the total seed lot coming from all the plants).

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.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; Article de revue (Article scientifique dans une revue à comité de lecture); International audience; The invitro effects of 6-MM and falcarindiol on the development of Alternaria dauci were analyzed. The results showed that A.dauci was significantly more susceptible to falcarindiol than to 6-MM. Experiments dealing with mixed solutions of 6-MM and falcarindiol indicated additive effects of the metabolites on growth inhibition. Permeabilization of the fungal plasma membrane was observed after falcarindiol treatment. In planta quantification of 6-MM/falcarindiol was performed on inoculated leaves of carrot genotypes. Significantly faster 6-MM production was observed in Bolero (partially resistant to A.dauci) than in Presto (susceptible). The falcarindiol levels were significantly higher in Bolero than in Presto.

Garlic ( Allium sativum L.) that is cultivated in Tunisia is heterogeneous and unclassified with no registered local cultivars. At present, the level of genetic diversity in Tunisian garlic is almost unknown. Inter Simple Sequence Repeats (ISSR) genetic markers were therefore used to assess the genetic diversity and its distribution in 31 Tunisian garlic accessions with 4 French classified clones used as control. It was the first time that ISSR markers were used to detect diversity in garlic. Seventeen ISSR primers were screened; seven primers detected 73 polymorphic bands. A high level of polymorphic loci (p) was found in Tunisian populations (54%). Nei’s total genetic diversity coefficient was 0.45 and 0.34 respectively for Tunisian and French garlic. Genetic distances observed between Tunisian accessions, ranged between 38.4 and 78.1%. Factor analysis of distances’ table (AFTD) did not classify accessions on the base of geographical origin or morpho-physiological characters, particularly bolting ability, but confirmed the appurtenance of analyzed accessions to s ativum botanical subspecies. There was sufficient diversity detected to start a national collection of garlic germplasm which is crucial for the conservation of genetic diversity and its valorization. Keywords: Allium sativum L., ISSR markers, genetic diversity, Tunisian garlic populations.

In most production areas, Alternaria leaf blight (ALB) is recognized as the most common and destructive foliage disease in carrot. To assess the genetic architecture of carrot ALB resistance, two parental coupling maps were developed with similar number of dominant markers (around 70), sizes (around 650 cM), densities (around 9.5 cM), and marker composition. The F(2:3) progenies were evaluated in field and tunnel for two scoring dates. The continuous distribution of the disease severity value indicated that ALB resistance is under polygenic control. Three QTLs regions were found on three linkage groups. Two of them were tunnel or field specific and were detected only at the second screening date suggesting that the expression of these two QTLs regions involved in resistance to Alternaria dauci might depend on environment and delay after infection.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; The interaction between Alternaria dauci and two carrot cultivars differing in their resistance to leaf blight was investigated by microscopy. The fungal development between 1 and 15 days post-inoculation was quite similar in the susceptible cv. Presto and the partially resistant cv. Texto: After conidial germination, leaf adhesion of the pathogen was achieved with mucilaginous filaments; hyphae penetrated the leaves directly with/without the formation of appressoria-like structures or via stomata; the fungus spread by epiphytic hyphae with hyphopodia and subcuticular mycelia. Intense necrotic plant cell reactions occurred under the fungal structures. At 21 days post-inoculation, typical features of fungal development were noted for each cultivar: growing hyphae emerged from stomata in cv. Presto, whereas conidiophores without conidia were observed in cv. Texto. Leaf tissues of both cultivars were strongly damaged and vesicle-like structures (assumed to be plant phenolics) were abundantly present between mesophyll cells. A real-time PCR method was developed for in planta quantification of A. dauci. Between 1 and 15 days post-inoculation, the fungal biomass was equivalent in the two cultivars and was about fourfold higher in cv. Presto than cv. Texto at 21 and 25 days post-inoculation. Taken together, our results indicated that A. dauci was able to colonize both cultivars in a similar manner during the first steps of the interaction, then fungal development in the partially resistant cultivar was restricted due to putative plant defence reactions. The results of this study enhance the overall understanding of infection processes in the A. dauci-carrot pathosystem

It’s been three years that the association Kaol Kozh carries the certification label « Légume Issu de Semence Paysanne », created in order to highlight the farmer’s know-how on seeds’ selection and multiplication in their farm. Addressed to the consumers, it involves all the economic agents of the vegetable sector (farmers, shippers, distributors…) that may be able to fully understand its stakes and requirements. A guidance problem of this mention has been raised, so as to make it grow and ensure its longevity for the future. The goal was also to increase farmer’s implication in the process. This report outlines chronologically the steps taken during my six months study. Different methods have been used, such as a bibliographic research, farmers’ phone interviews, a field evaluation during the 2020 controls, a teamwork with Ecocert… This work led to the creation of a synthetic document on the certification principles and rules, an enhancement of the inspection grid, controls adjustment to Ecocert standards and the drafting of technical data sheets. Nevertheless, building a strong certification is a continuous process that will need reviews and improvements in an incremental way.; L’association Kaol Kozh porte depuis 3 ans la mention « Légume Issu de Semence Paysanne », créée dans le but de valoriser le savoir-faire de sélection et multiplication des semences par les paysans. A destination des consommateurs, elle implique tous les acteurs de la filière (producteurs, expéditeurs, distributeurs…), qui doivent pouvoir en comprendre pleinement ses enjeux et ses attentes. Il s’est posé un problème de cadrage de cette mention, afin de lui permettre de prendre de l’ampleur et d’assurer sa pérennité dans le futur. Le but étant aussi d’augmenter l’implication des producteurs dans la démarche. Ce rapport retrace chronologiquement les étapes suivies pendant les six mois de mon étude. Différentes méthodes ont été utilisées parmi lesquelles une recherche bibliographique, des entretiens téléphoniques de producteurs, une évaluation sur le terrain lors de la campagne de contrôle, une collaboration avec Ecocert… Ce travail a permis la création d’un « Document unique » condensant tous les principes et règles de la certification, une amélioration de la grille de contrôle, une adaptation des contrôles à Ecocert ainsi que l’élaboration de fiches techniques. La construction d’une mention solide reste néanmoins un processus continu, qu’il faudra réviser et améliorer de manière incrémentielle.

Since 2006, French garlic producers has been facing a new disease called garlic rot. It is caused by a fungus from the genus Fusarium which species has not been identified on French territory yet. Identifying the responsible species requires evaluation of the pathogenicity of the studied strains. Three inoculation methods of Fusarium on garlic were tested: deposition of a PDA explant on a wound; immersion of cloves in a spores suspension; deposition of 10 μL of spores suspension in a wound. The technique of inoculation by immersion in a suspension seems to be the most suitable because it allows to reproduce true symptoms from the 4th week. The two other methods enhance the mycelial development on the surface, with no apparent symptoms in six weeks. An endophytic microorganism was present in asymptomatic cloves and morphologically resembles the Fusarium genus. The study of pedoclimatic conditions allows to characterize the environment in which garlic is cultivated in France. These results will be useful for understanding the pathogen development once identified. The installation of insect-proof nets on crop-producing garlic seeds influences the temperature and humidity of the plot, but in limited proportions. Analysis of the entomological pressure in the plot did not confirm the presence of Clinodiplosis cilicrus as a potentially active species in the propagation of Fusarium spores. The insect was not present in plots in 2017.; Depuis 2006, les producteurs d’ail français sont confrontés à une nouvelle maladie, appelée fusariose de l’ail. Elle est due à un champignon du genre Fusarium dont l’espèce n’a pas encore été identifiée sur le territoire français. Identifier les espèces responsables de la maladie nécessite l’évaluation de la pathogénicité des souches étudiées. Trois méthodes d’inoculation de Fusarium sur ail sont testées : dépôt d’un explant de gélose PDA sur une blessure ; immersion de caïeux dans une suspension de spores ; dépôt de 10 µL de suspension de spores dans une blessure. La technique d’inoculation par immersion dans une suspension semble la plus adaptée car elle permet de reproduire de vrais symptômes dès la 4e semaine. Les deux autres méthodes favorisent un développement mycélien en surface, sans symptômes apparents en six semaines. Un micro-organisme endophyte était présent dans les caïeux asymptomatiques et ressemble, morphologiquement, au genre Fusarium. L’étude des conditions pédoclimatiques permet de caractériser l’environnement dans lequel est cultivé l’ail, en France. Ces résultats seront utiles pour comprendre le développement du pathogène une fois identifié. La pose de filets anti-insectes sur les cultures de production d’ail semences influence la température et l’hygrométrie de la parcelle, mais dans des proportions limitées. L’analyse de la pression entomologique en parcelle n’a pas permis de confirmer la présence de Clinodiplosis cilicrus comme espèce potentiellement active dans la propagation des spores de Fusarium. L’insecte n’était pas présent en parcelle en 2017.