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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.

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.

—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.

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.

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.

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.

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).

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.

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.

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.

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.

Because of potential benefits on human health, the content of quercetin, the major flavonol found in onion (Allium cepa), could become a selection trait in breeding programs. Total flavonol concentration in onion was examined by spectrophotometric analysis at 374 nm in three long-day hybrid cultivars grown at three locations (Parma, Idaho; Grand Rapids, Mich; Elba, N.Y.), and in three shortday hybrid cultivars grown at one location in Georgia in three different fields. Mean total flavonol concentrations for long-day hybrids ranged from 176 to 232 mg·kg-1 (ppm) fresh weight and 110 to 173 mg·kg-1 fresh weight among short-day cultivars. No significant effect of location (state or field) was detected (P > 0.05). A significant (P > 0.05) cultivar by field interaction was detected in the short-day experiment, with the hybrid `Sweet Vidalia' showing significant differences among fields. Overall, our results suggest that quercetin content in onion, as expressed by the total flavonol content, does not vary depending on the growing origin, and therefore could be evaluated effectively in breeding or commercial material.

There was an error in affiliation 1 for all listed authors. Affiliation 1 should be: Universite d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR 4207 QUASAV, PRES L'UNAM, Angers, France

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; Background: Selection of genes involved in metabolic pathways could target them differently depending on the position of genes in the pathway and on their role in controlling metabolic fluxes. This hypothesis was tested in the carotenoid biosynthesis pathway using population genetics and phylogenetics. Methodology/Principal Findings: Evolutionary rates of seven genes distributed along the carotenoid biosynthesis pathway, IPI, PDS, CRTISO, LCYB, LCYE, CHXE and ZEP, were compared in seven dicot taxa. A survey of deviations from neutrality expectations at these genes was also undertaken in cultivated carrot (Daucus carota subsp. sativus), a species that has been intensely bred for carotenoid pattern diversification in its root during its cultivation history. Parts of sequences of these genes were obtained from 46 individuals representing a wide diversity of cultivated carrots. Downstream genes exhibited higher deviations from neutral expectations than upstream genes. Comparisons of synonymous and nonsynonymous substitution rates between genes among dicots revealed greater constraints on upstream genes than on downstream genes. An excess of intermediate frequency polymorphisms, high nucleotide diversity and/or high differentiation of CRTISO, LCYB1 and LCYE in cultivated carrot suggest that balancing selection may have targeted genes acting centrally in the pathway. Conclusions/Significance: Our results are consistent with relaxed constraints on downstream genes and selection targeting the central enzymes of the carotenoid biosynthesis pathway during carrot breeding history.

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.

The morphological variation and the isozymic polymorphism in 19 asparagus accessions currently used in cultivation and breeding are described. Moreover 2 wild populations from Turkey were added in the isozymic study. Characters of ramification height permit to separate accessions usually cultivated for white asparagus and accessions usually cultivated for green asparagus. Starch and polyacrylamide gel electrophoresis was realized to assay 7 enzyme systems. 29 polymorphic bands were taken into account in the study. Four accessions show specific bands for glutamate oxaloacetate transaminase, shikimate dehydrogenase and alcohol dehydrogenase. In particular, the two populations from Turkey and one population traditionally cultivated in local area of Spain are well differentiated from the remaining accessions. Accessions from the United States representing different selections are relatively well separated from each other.

Carotenogenesis has been extensively studied in fruits and flower petals. Transcriptional regulation is thought to be the major factor in carotenoid accumulation in these organs. However, little is known about regulation in root organs. The root carotenoid content of carrot germplasm varies widely. The present study was conducted to investigate transcriptional regulation of carotenoid biosynthesis genes in relation to carotenoid accumulation during early carrot root development and up to 3 months after sowing. HPLC carotenoid content analysis and quantitative RT-PCR were compared to quantify the expression of eight genes encoding carotenoid biosynthesis enzymes during the development of white, yellow, orange, and red carrot roots. The genes chosen encode phytoene synthase (PSY1 and PSY2), phytoene desaturase (PDS), zeta-carotene desaturase (ZDS1 and ZDS2), lycopene epsilon-cyclase (LCYE), lycopene beta-cyclase (LCYB1), and zeaxanthin epoxidase (ZEP). All eight genes were expressed in the white cultivar even though it did not contain carotenoids. By contrast with fruit maturation, the expression of carotenogenic genes began during the early stages of development and then progressively increased for most of these genes during root development as the total carotenoid level increased in coloured carrots. The high expression of genes encoding LCYE and ZDS noted in yellow and red cultivars, respectively, might be consistent with the accumulation of lutein and lycopene, respectively. The results showed that the accumulation of total carotenoids during development and the accumulation of major carotenoids in the red and yellow cultivars might partially be explained by the transcriptional level of genes directing the carotenoid biosynthesis pathway.

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; Haploidization in onion (Allium cepa L.) using immature flower buds simulates zygotic embryogenesis with no fecundation. In order to know the involvement of polyamines (PAs) in this process, we determined the concentration of endogenous PAs in flower buds and experimented the addition of various combinations of PA molecules in the medium. At the inoculation stage, high levels of free and conjugated spermidine and low putrescine + hydroxyputrescine/spermidine + spermine ratio characterized the highest responsive varieties. During in vitro culture, high levels of putrescine and its derivatives characterized the lowest responsive varieties, whereas high levels of spermidine and spermine characterized responsive varieties. The putrescine + hydroxyputrescine + homospermidine/spermidine + spermine ratio remained low in responsive varieties. The addition of spermidine or spermine (2 x 10(-3) M) to the culture medium improved significantly the embryo production. Our results suggest that the arginine decarboxylase pathway is involved in PA biosynthesis during the in vitro culture of flower buds. Our study showed that specific ratios of PAs are required for successful gynogenesis in onion

The flavonol quercetin has been reported as having many health benefits, including a reduction in the risk of developing cardiovascular disease, stroke, and some types of cancer. The overall content of quercetin in onion was examined in four yellow varieties (`Rio Rita', `RNX 10968', `Predator', and `Tamara') and one red variety purchased at a local grocery store. Each bulb was quartered, with one quarter saved as a control and the other three quarters subjected to three cooking treatments that simulated common domestic processing methods of preparing onion. The treatments included sautéing in sunflower oil for 5 minutes at 93 °C, baking for 15 min. at 176 °C, and boiling for 5 minutes in distilled water. Samples were frozen in liquid nitrogen, ground to a fine powder, blended with 80% EtOH, and filtered for quercetin extraction. The filtrate was then analyzed with a spectrophotometer (uv 374 nm). Quercetin concentrations were obtained in mg quercetin/kg fresh weight of tissue by regressing spectrophotometer readings onto a standard curve. Significant differences between varieties were found when examining fresh samples alone with the red variety containing the highest content of quercetin. Results of cooking showed that sautéing produced an overall 27% gain in quercetin concentration (significantly higher than the fresh control), baking produced an overall 4% gain in concentration (insignificant from the fresh control), while boiling produced an overall 18% loss in quercetin concentration (significantly lower than the fresh control).