Microsatellite analysis and marker development in garlic: distribution in EST sequence, genetic diversity analysis, and marker transferability across Alliaceae.

Allium vegetables, such as garlic and onion, have understudied genomes and limited molecular resources, hindering advances in genetic research and breeding of these species. In this study, we characterized and compared the simple sequence repeats (SSR) landscape in the transcriptomes of garlic and related Allium (A. cepa, A. fistulosum, and A. tuberosum) and non-Allium monocot species. In addition, 110 SSR markers were developed from garlic ESTs, and they were characterized-along with 112 previously developed SSRs-at various levels, including transferability across Alliaceae species, and their usefulness for genetic diversity analysis. Among the Allium species analyzed, garlic ESTs had the highest overall SSR density, the lowest frequency of trinucleotides, and the highest of di- and tetranucleotides. When compared to more distantly related monocots, outside the Asparagales order, it was evident that ESTs of Allium species shared major commonalities with regards to SSR density, frequency distribution, sequence motifs, and GC content. A significant fraction of the SSR markers were successfully transferred across Allium species, including crops for which no SSR markers have been developed yet, such as leek, shallot, chives, and elephant garlic. Diversity analysis of garlic cultivars with selected SSRs revealed 36 alleles, with 2-5 alleles/locus, and PIC = 0.38. Cluster analysis grouped the accessions according to their flowering behavior, botanical variety, and ecophysiological characteristics. Results from this study contribute to the characterization of Allium transcriptomes. The new SSR markers developed, along with the data from the polymorphism and transferability analyses, will aid in assisting genetic research and breeding in garlic and other Allium.

Onion Hybrid Seed Production: Relation with Nectar Composition and Flower Traits.

Onion (Allium cepa L.) is one of the main vegetable crops. Pollinators are required for onion seed production, being honeybees the most used. Around the world, two types of onion varieties are grown: open pollinated (OP) and hybrids. Hybrids offer numerous advantages to growers, but usually have lower seed yields than OP cultivars, which in many cases compromise the success of new hybrids. As pollination is critical for seed set, understanding the role of floral rewards and attractants to pollinator species is the key to improve crop seed yield. In this study, the correlation of nectar-analyzed compounds, floral traits, and seed yield under open field conditions in two experimental sites was determined. Nectar composition was described through the analysis of sugars, phenol, and alkaloid compounds. Length and width of the style and tepals of the flowers were measured to describe floral traits. Floral and nectar traits showed differences among the studied lines. For nectar traits, we found a significant influence of the environment where plants were cultivated. Nonetheless, flower traits were not influenced by the experimental sites. The OP and the male-sterile lines (MSLs) showed differences in nectar chemical composition and floral traits. In addition, there were differences between and within MSLs, some of which were correlated with seed yield, bringing the opportunity to select the most productive MSL, using simple determinations of morphological characters like the length of the style or tepals size.

Dataset on absorption spectra and bulb concentration of phenolic compounds that may interfere with onion pyruvate determinations.

We present data on absorption spectra (400-540 nm) and concentration of phenolic compounds quercetin, myricetin, kaempferol, rutin, catechin, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), in yellow, red and white onions. These data are related to the article entitled "Variability in spectrophotometric pyruvate analyses for predicting onion pungency and nutraceutical value" (Beretta et al., 2017) [1]. Given the relevance of pyruvate determinations for estimating onion pungency and functional value, it is important to identify compounds that can interfere with pyruvate determinations when using two previously published analytical procedures, namely Schwimmer and Weston (1961) (SW) [2] and Anthon and Barret (2002) (AB) [3], which are based on spectrophotometry and light-absorbance at 420 nm and 515 nm, respectively. The data presented in this article are absorption spectra for 7 onion phenolic compounds in the range 400-540 nm, which include wavelengths used by the two pyruvate analytical methods (Schwimmer and Weston, 1961; Anthon and Barret, 2002) [2,3] that were compared in our reference article (Beretta et al., 2017) [1]. Additionally, bulb content data for these 7 phenolic compounds in onion cultivars and F2 progenies with different bulb color were included to allow further analyses.

Variability in spectrophotometric pyruvate analyses for predicting onion pungency and nutraceutical value.

Onion pyruvate concentration is used as a predictor of flavor intensity and nutraceutical value. The protocol of Schwimmer and Weston (SW) (1961) is the most widespread methodology for estimating onion pyruvate. Anthon and Barret (AB) (2003) proposed modifications to this procedure. Here, we compared these spectrophotometry-based procedures for pyruvate analysis using a diverse collection of onion cultivars. The SW method always led to over-estimation of pyruvate levels in colored, but not in white onions, by up to 65%. Identification of light-absorbance interfering compounds was performed by spectrophotometry and HPLC analysis. Interference by quercetin and anthocyanins, jointly, accounted for more than 90% of the over-estimation of pyruvate. Pyruvate determinations according to AB significantly reduced absorbance interference from compounds other than pyruvate. This study provides evidence about the mechanistic basis underlying differences between the SW and AB methods for indirect assessment of onion flavor and nutraceutical value.

Catechin and quercetin attenuate adipose inflammation in fructose-fed rats and 3T3-L1 adipocytes.

SCOPE: This study evaluated the capacity of dietary catechin (C), quercetin (Q), and the combination of both (CQ), to attenuate adipose inflammation triggered by high fructose (HFr) consumption in rats and by tumor necrosis factor alpha (TNF-α) in 3T3-L1 adipocytes. METHODS AND RESULTS: In rats, HFr consumption for 6 wk caused dyslipidemia, insulin resistance, reduced plasma adiponectin, adiposity, and adipose tissue inflammation. Dietary supplementation with 20 mg/kg/day of C, Q, and CQ improved all these parameters. In 3T3-L1 adipocytes, C and Q attenuated TNF-α-induced elevated protein carbonyls, increased proinflammatory cytokine expression (MCP-1, resistin), and decreased adiponectin. The protective effects of C and Q on adipose inflammation are in part associated with their capacity to (i) decrease the activation of the mitogen-activated kinases (MAPKs) JNK and p38; and (ii) prevent the downregulation of PPAR-γ. In summary, C and Q, and to a larger extent the combination of both, attenuated adipose proinflammatory signaling cascades and regulated the balance of molecules that improve (adiponectin) or impair (TNF-α, MCP-1, resistin) insulin sensitivity. CONCLUSION: Together, these findings suggest that dietary Q and C may have potential benefits in mitigating MetS-associated adipose inflammation, oxidative stress, and insulin resistance.

Nectar and flower traits of different onion male sterile lines related to pollination efficiency and seed yield of F1 hybrids.

Honey bees are the main pollinators of onion crops for seed production, but owing to low attractiveness of flowers, pollination is often inadequate. Pollination problems result in low seed yields. This problem is accentuated when male sterile lines (MSL) are used to produce hybrid onion seeds. In this study, the effect of floral attributes and nectar composition on the preference of honey bees of four MSLs and one onion open pollinated cultivar were assessed. The chemical composition of nectar was described through the analysis of sugars, trace elements, volatile organic compounds, and phenol compounds. The samples studied showed qualitative and quantitative differences in the analyzed traits of flowers and nectar among the different lines. Furthermore, field observations showed a great difference on the number of bee visits and seed yield among the onion lines analyzed. For the first time, this study demonstrates that there are marked differences in the chemical composition of nectar and floral morphology between open pollinated and MSLs and also within MSLs. In addition, these differences were correlated with the number of visits and seed yield. Therefore, it would be possible to select indirectly the most promising productive MSL using simple determinations of chemical compounds or floral morphological characters.

Molecular mapping of vernalization requirement and fertility restoration genes in carrot.

Carrot (Daucus carota L.) is a cool-season vegetable normally classified as a biennial species, requiring vernalization to induce flowering. Nevertheless, some cultivars adapted to warmer climates require less vernalization and can be classified as annual. Most modern carrot cultivars are hybrids which rely upon cytoplasmic male-sterility for commercial production. One major gene controlling floral initiation and several genes restoring male fertility have been reported but none have been mapped. The objective of the present work was to develop the first linkage map of carrot locating the genomic regions that control vernalization response and fertility restoration. Using an F(2) progeny, derived from the intercross between the annual cultivar 'Criolla INTA' and a petaloid male sterile biennial carrot evaluated over 2 years, both early flowering habit, which we name Vrn1, and restoration of petaloid cytoplasmic male sterility, which we name Rf1, were found to be dominant traits conditioned by single genes. On a map of 355 markers covering all 9 chromosomes with a total map length of 669 cM and an average marker-to-marker distance of 1.88 cM, Vrn1 mapped to chromosome 2 with flanking markers at 0.70 and 0.46 cM, and Rf1 mapped to chromosome 9 with flanking markers at 4.38 and 1.12 cM. These are the first two reproductive traits mapped in the carrot genome, and their map location and flanking markers provide valuable tools for studying traits important for carrot domestication and reproductive biology, as well as facilitating carrot breeding.

Effect of processing and cooking conditions on onion (Allium cepa L.) induced antiplatelet activity and thiosulfinate content.

Allium vegetables serve as sources of antiplatelet agents that may contribute to the prevention of cardiovascular disease. However, onion and garlic, the major Allium species, are usually cooked before consumption. Here, we examined the effect of cooking on onion in vitro antiplatelet activity (IVAA). Two different cooking systems (convection oven and microwaves) and several time-temperature variables were tested on whole bulbs, quarters of bulbs, and completely crushed bulbs, monitoring the degradation of sulfur antiplatelet compounds (e.g., thiosulfinates) by analysis of pyruvate levels. Although heating was, in general, detrimental for onion IVAA, the extent of this effect varied greatly, from unaffected antiplatelet activity (AA) (i.e., similar to raw onion) to a complete lost of activity, depending upon the manner in which onions were prepared prior to heating, the cooking method, and the intensity of the heat treatment. "Whole", "quarters", and "crushed" onions lost their IVAA after 30, 20, and 10 min of oven heating, respectively. The longer retainment of AA in intact bulbs was attributed to a later alliinase inactivation. Proaggregatory effects observed in samples subjected to the most intense oven and microwave heat treatments suggest that extensively cooked onions may stimulate rather than inhibit platelet aggregation. The efficacy of Allium species as antiplatelet agents, as affected by preparation and cooking conditions, is discussed.

Effect of cooking on garlic (Allium sativum L.) antiplatelet activity and thiosulfinates content.

The raw form of garlic and some of its preparations are widely recognized as antiplatelet agents that may contribute to the prevention of cardiovascular disease. Herein, we examined the in-vitro antiaggregatory activity (IVAA) of human blood platelets induced by extracts of garlic samples that were previously heated (in the form of crushed versus uncrushed cloves) using different cooking methods and intensities. The concentrations of allicin and pyruvate, two predictors of antiplatelet strength, were also monitored. Oven-heating at 200 degrees C or immersing in boiling water for 3 min or less did not affect the ability of garlic to inhibit platelet aggregation (as compared to raw garlic), whereas heating for 6 min completely suppressed IVAA in uncrushed, but not in previously crushed, samples. The latter samples had reduced, yet significant, antiplatelet activity. Prolonged incubation (more than 10 min) at these temperatures completely suppressed IVAA. Microwaved garlic had no effect on platelet aggregation. However, increasing the concentration of garlic juice in the aggregation reaction had a positive IVAA dose response in crushed, but not in uncrushed, microwaved samples. The addition of raw garlic juice to microwaved uncrushed garlic restored a full complement of antiplatelet activity that was completely lost without the garlic addition. Garlic-induced IVAA was always associated with allicin and pyruvate levels. Our results suggest that (1) allicin and thiosulfinates are responsible for the IVAA response, (2) crushing garlic before moderate cooking can reduce the loss of activity, and (3) the partial loss of antithrombotic effect in crushed-cooked garlic may be compensated by increasing the amount consumed.

QTL affecting soluble carbohydrate concentrations in stored onion bulbs and their association with flavor and health-enhancing attributes.

Onion bulbs accumulate fructans, a type of soluble carbohydrate associated with lower rates of colorectal cancers. Higher fructan concentrations in bulbs are correlated with higher pungency, longer dormancy, and greater onion-induced antiplatelet activity (OIAA). We analyzed replicated field trials of a segregating family for types and concentrations of soluble carbohydrates in onion bulbs 90 days after harvest. Means were adjusted using dry weight as the covariant to reveal highly significant (P < 0.001) differences among parents and families for glucose, fructose, sucrose, and the fructans 1-kestose, neokestose, and (6G,1)-nystose. Fructan concentrations showed significant (P < 0.05) phenotypic correlations with each other and with sucrose, pungency, and OIAA. These observations are consistent with the hypothesis that onion bulbs accumulating fructans take up or retain less water, concentrating both soluble carbohydrates and thiosulfinates responsible for pungency and OIAA. Interval mapping of family means from the covariant analyses revealed regions on linkage groups A and D significantly (LOD > 2.68) affecting soluble carbohydrate concentrations. The enzyme catalyzing the first step of fructan polymerization, 1-sucrose-sucrose fructosyltransferase (1-SST), mapped independently of these genomic regions. One region on linkage group D near an acid-invertase gene was significantly (LOD = 3.45) associated with sucrose concentrations. This study reveals that the accumulation of sucrose in stored onion bulbs may allow for the combination of sweeter flavor with significant OIAA.