RESUMEN
BACKGROUND: Next generation sequencing has allowed the discovery of miRNA isoforms, termed isomiRs. Some isomiRs are derived from imprecise processing of pre-miRNA precursors, leading to length variants. Additional variability is introduced by non-templated addition of bases at the ends or editing of internal bases, resulting in base differences relative to the template DNA sequence. We hypothesized that some component of the isomiR variation reported so far could be due to systematic technical noise and not real. RESULTS: We have developed the XICRA pipeline to analyze small RNA sequencing data at the isomiR level. We exploited its ability to use single or merged reads to compare isomiR results derived from paired-end (PE) reads with those from single reads (SR) to address whether detectable sequence differences relative to canonical miRNAs found in isomiRs are true biological variations or the result of errors in sequencing. We have detected non-negligible systematic differences between SR and PE data which primarily affect putative internally edited isomiRs, and at a much smaller frequency terminal length changing isomiRs. This is relevant for the identification of true isomiRs in small RNA sequencing datasets. CONCLUSIONS: We conclude that potential artifacts derived from sequencing errors and/or data processing could result in an overestimation of abundance and diversity of miRNA isoforms. Efforts in annotating the isomiRnome should take this into account.
Asunto(s)
Análisis de Datos , MicroARNs , Secuenciación de Nucleótidos de Alto Rendimiento , MicroARNs/genética , Análisis de Secuencia de ARN , Secuenciación del ExomaRESUMEN
Salicylic acid (SA) promotes plant defense responses against toxic metal stresses. The present study addressed the hypothesis that 8-h SA pretreatment, would alter membrane lipids in a way that would protect against Cd toxicity. Flax seeds were pre-soaked for 8h in SA (0, 250 and 1000µM) and then subjected, at seedling stage, to cadmium (Cd) stress. At 100µM CdCl2, significant decreases in the percentages of phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylethanolamine (PE) and monogalactosyldiacylglycerol (MGDG) and changes in their relative fatty acid composition were observed in Cd-treated roots in comparison with controls. However, in roots of 8-h SA pretreated plantlets, results showed that the amounts of PC and PE were significantly higher as compared to non-pretreated plantlets. Additionally, in both lipid classes, the proportion of linolenic acid (18:3) increased upon the pretreatment with SA. This resulted in a significant increase in the fatty acid unsaturation ratio of the root PC and PE classes. As the exogenous application of SA was found to be protective of flax lipid metabolism, the possible mechanisms of protection against Cd stress in flax roots were discussed.
Asunto(s)
Cloruro de Cadmio/metabolismo , Lino/efectos de los fármacos , Lípidos de la Membrana/análisis , Fosfolípidos/análisis , Raíces de Plantas/efectos de los fármacos , Sustancias Protectoras/farmacología , Ácido Salicílico/farmacología , Contaminantes del Suelo/análisis , Cloruro de Cadmio/análisis , Ácidos Grasos/análisis , Lino/química , Galactolípidos/análisis , Metabolismo de los Lípidos/efectos de los fármacos , Fosfatidiletanolaminas , Raíces de Plantas/química , Plantones/química , Plantones/efectos de los fármacosRESUMEN
Total and individual glucosinolate (GSL) content of leaves of vegetable turnip rape (Brassica rapa L. var. rapa) was determined in a set of 45 varieties consisting in early, medium and late types grown at two locations in northwestern Spain. The objectives were to determine the diversity among varieties in GSL content and to relate that variation with earliness and plant habit. Eight GSL were identified, being two aliphatic GSL, gluconapin (84.4 % of the total GSL) and glucobrassicanapin (7.2 % of the total GSL) the most abundant. Indolic and aromatic GSL content were low but also showed significant differences among varieties. Differences in total and individual GSL content were found among varieties, plant habit groups, and earliness groups. Total GSL content ranged from 19 to 37.3 µmol g(-1) dw in early and extra-late groups, respectively, and from 19.5 to 36.3 µmol g(-1) dw for turnips and turnip greens groups, respectively. These differences were consistent to values found for gluconapin content where the turnip group had the highest values (31.8 µmol g(-1) dw) and the turnip top group had the lowest (15.7 µmol g(-1) dw). Two varieties, MBG-BRS0429 and MBG-BRS0550 (from turnip greens and extra-late groups) and MBG-BRS0438 (from turnips and late groups), stood out as they had the highest total GSL content and could be used as a good source of these beneficial bioactive compounds. Elucidation of genetic diversity among crops can provide useful information to assist plant breeders to design improved breeding strategies in order to obtain varieties rich on GSL.
Asunto(s)
Brassica rapa/química , Cruzamiento , Productos Agrícolas/química , Glucosinolatos/análisis , Hojas de la Planta/química , Raíces de Plantas/química , Verduras/química , Brassica napus , Brassica rapa/genética , Brassica rapa/crecimiento & desarrollo , Productos Agrícolas/genética , Productos Agrícolas/crecimiento & desarrollo , Dieta , Glucosinolatos/genética , Humanos , Indoles/análisis , España , Especificidad de la Especie , Verduras/genética , Verduras/crecimiento & desarrolloRESUMEN
Brassica oleracea var. acephala (kale) is a cruciferous vegetable widely cultivated for its leaves and flower buds in Europe and a food of global interest as a "superfood". Brassica crops accumulate phytochemicals called glucosinolates (GSLs) which play an important role in plant defense against biotic stresses. Studies carried out to date suggest that GSLs may have a role in the adaptation of plants to different environments, but direct evidence is lacking. We grew two kale populations divergently selected for high and low indol-3-ylmethylGSL (IM) content (H-IM and L-IM, respectively) in different environments and analyzed agronomic parameters, GSL profiles and metabolomic profile. We found a significant increase in fresh and dry foliar weight in H-IM kale populations compared to L-IM in addition to a greater accumulation of total GSLs, indole GSLs and, specifically, IM and 1-methoxyindol-3-ylmethylGSL (1MeOIM). Metabolomic analysis revealed a significant different concentration of 44 metabolites in H-IM kale populations compared to L-IM. According to tentative peak identification from MS interpretation, 80% were phenolics, including flavonoids (kaempferol, quercetin and anthocyanin derivates, including acyl flavonoids), chlorogenic acids (esters of hydroxycinnamic acids and quinic acid), hydroxycinnamic acids (ferulic acid and p-coumaric acid) and coumarins. H-IM kale populations could be more tolerant to diverse environmental conditions, possibly due to GSLs and the associated metabolites with predicted antioxidant potential.
RESUMEN
Brassica oleracea L. crops including kales, cabbages, and Tronchuda cabbages are widely grown in northwestern Spain and Portugal but little information is available on leaf glucosinolate content of these crops. The objectives were to determine the diversity for the total glucosinolate content and profile on leaves in a collection of 153 kales, 26 cabbages, and three Tronchuda cabbages varieties grown at two growing seasons and to determine the seasonal variation of glucosinolates in cabbages and Tronchuda cabbage varieties. Sinigrin, glucoiberin, and glucobrassicin were the major glucosinolates found in kales. Glucoiberin was the most common glucosinolate in Tronchuda cabbages in both planting seasons and in cabbages sown in fall season whereas glucobrassicin and glucoiberin were the most common glucosinolates in cabbages in spring season. In kales the total glucosinolate content ranged from 11.0 to 53 micromol g(-1) dw, with a mean value of 26.3 micromol g(-1) dw. Four kale varieties (MBG-BRS0468, MBG-BRS0476, MBG-BRS0060 and MBG-BRS0223) showed the highest total sinigrin or glucobrassicin contents. So, they could be good candidates for future breeding programs. In cabbages, the total glucosinolate content ranged from 10.9 to 27 g(-1) dw. Total glucosinolate concentration during spring sowing (22 micro mg(-1) dw) was higher than those in fall sowing (13 micro mg(-1) dw). Regarding both high glucosinolate content and the agronomic value, MBG-BRS0057 and MBG-BRS0074 could be good sources of beneficial glucosinolates. The presence of high concentrations of sinigrin, glucoiberin, and glucobrassicin warrant further search into their potential use to enhance the level of these important phytochemicals in these edible crops.
Asunto(s)
Brassica/metabolismo , Productos Agrícolas/metabolismo , Glucosinolatos/metabolismo , Estaciones del Año , Brassica/química , Brassica/crecimiento & desarrollo , Productos Agrícolas/química , Productos Agrícolas/crecimiento & desarrollo , Glucosinolatos/análisis , EspañaRESUMEN
Glucosinolate levels in leaves were determined in a collection of 113 varieties of turnip greens (Brassica rapa L.) from northwestern Spain grown at two sites. Sensorial attributes were also assessed by a consumer panel. The objectives were to determine the diversity among varieties in total glucosinolate content and glucosinolate profile and to evaluate their sensory attributes in relation to glucosinolate content for breeding purposes. Sixteen glucosinolates were identified, being the aliphatic glucosinolates, gluconapin and glucobrassicanapin the most abundant. Other aliphatic glucosinolates, such as progoitrin, glucoalyssin, and gluconapoleiferin were relatively abundant in varieties with a different glucosinolate profile. Indolic and aromatic glucosinolate concentrations were low and showed few differences among varieties. Differences in total glucosinolate content, glucosinolate profile and bitterness were found among varieties, with a total glucosinolate content ranging from 11.8 to 74.0micromolg(-1) dw at one site and from 7.5 to 56.9micromolg(-1) dw at the other site. Sensory analysis comparing bitterness with variation in glucosinolate, gluconapin and glucobrassicanapin concentrations suggested that these compounds and their breakdown products are not the only determinants of the characteristic flavour of this vegetable. Other phytochemicals are probably involved on the characteristic bitter flavour. The varieties MBG-BRS0132, MBG-BRS0082, MBG-BRS0173, and MBG-BRS0184 could be good candidates for future breeding programs since they had high total glucosinolate content and good agronomic performance. The presence of glucoraphanin in some varieties should be studied more extensively, because this aliphatic glucosinolate is the precursor of sulforaphane, a potent anti-cancer isothiocyanate.
Asunto(s)
Brassica rapa/genética , Variación Genética , Glucosinolatos/biosíntesis , Brassica napus/genética , Brassica napus/metabolismo , Brassica rapa/metabolismo , Productos Agrícolas/genética , Productos Agrícolas/metabolismo , Glucosinolatos/aislamiento & purificación , Humanos , España , GustoRESUMEN
Interest in use of flax (Linum usitatissimum L.) as cadmium (Cd)-accumulating plant for phytoextraction of contaminated soils opened up a new and promising avenue toward improving tolerance of its varieties and cultivars to Cd stress. The aim of this study is to get insights into the mechanisms of Cd detoxification in cell membranes, by exploring the effects of salicylic acid (SA)-induced priming on fatty acids and lipid composition of flax plantlets, grown for 10 days with 50 and 100 µM Cd. At leaf level, levels of monogalactosyldiacylglycerol (MGDG), phosphatidylcholine (PC), phosphatidylglycerol (PG), and neutral lipids (NL) have shifted significantly in flax plantlets exposed to toxic CdCl2 concentrations, as compared to that of the control. At 100 µM Cd, the linoleic acid (C18:2) decreases mainly in digalactosyldiacylglycerol (DGDG) and all phospholipid species, while linolenic acid (C18:3) declines mostly in MGDG and NL. Conversely, at the highest concentration of the metal, SA significantly enhances the levels of MGDG, PG and phosphatidic acid (PA), and polyunsaturated fatty acids mainly C18:2 and C18:3. Furthermore, SA pretreatment seems to reduce the Cd-induced alterations in both plastidial and extraplastidial lipid classes, but preferentially preserves the plastidial lipids by acquiring higher levels of polyunsaturated fatty acids. These results suggest that flax plantlets pretreated with SA exhibits more stability of their membranes under Cd-stress conditions.
Asunto(s)
Cloruro de Cadmio/metabolismo , Lino/química , Lípidos de la Membrana/análisis , Hojas de la Planta/química , Plastidios/química , Ácido Salicílico/farmacología , Contaminantes del Suelo/análisis , Absorción Fisicoquímica , Biodegradación Ambiental , Cloruro de Cadmio/análisis , Cloruro de Cadmio/aislamiento & purificación , Ácidos Grasos/análisis , Galactolípidos/análisis , Fosfolípidos/análisis , Hojas de la Planta/efectos de los fármacos , Plastidios/efectos de los fármacos , Contaminantes del Suelo/aislamiento & purificaciónRESUMEN
The potential of near infrared spectroscopy (NIRS) for determining the acid detergent fiber (ADF) in the seed of oilseed Brassica (fam. Brassicaceae) was assessed. One hundred and fifty accessions belonging to the species Indian mustard (Brassica juncea L. Czern.& Coss.), Ethiopian mustard (B. carinata A. Braun) and rapeseed (B. napus L.) were scanned by NIRS as intact and ground seed, and their ADF values were regressed against different spectra transformations by modified partial least squares regression. The coefficients of determination in the external validation (r(2)) for intact and ground seed were 0.83 and 0.85, respectively. The standard deviation to standard error of prediction ratio and range to standard error of prediction ratio were 2.40 and 10.75 for intact seed and 2.62 and 11.76 for ground seed. No significant differences in the prediction were found for both sample presentations. Effects of the C-H and O-H groups of lipids and water, respectively, as well as protein and chlorophyll, were most important in modeling these equations.
Asunto(s)
Brassica/química , Fibras de la Dieta/análisis , Semillas/química , Espectroscopía Infrarroja Corta , Brassica napus/química , Planta de la Mostaza/química , Extractos Vegetales/químicaRESUMEN
Cadmium (Cd) disrupts the normal growth and development of plants, depending on their tolerance to this toxic element. The present study was focused on the impacts of exogenous salicylic acid (SA) on the response and regulation of the antioxidant defense system and membrane lipids to 16-day-old flax plantlets under Cd stress. Exposure of flax to high Cd concentrations led to strong inhibition of root growth and enhanced lipid peroxides, membrane permeability, protein oxidation, and hydrogen peroxide (H2O2) production to varying degrees. Concomitantly, activities of the antioxidant enzymes catalase (CAT, EC 1.11.1.6), guaïcol peroxydase (GPX, EC 1.11.1.7), ascorbate peroxydase (APX, EC 1.11.1.11), and superoxide dismutase (SOD, EC 1.15.1.1), and the total antioxidant capacities (2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP)) were significantly altered by Cd. In contrast, exogenous SA greatly reduced the toxic effects of Cd on the root growth, antioxidant system, and membrane lipid content. The Cd-treated plantlets pre-soaked with SA exhibited less lipid and protein oxidation and membrane alteration, as well as a high level of total antioxidant capacities and increased activities of antioxidant enzymes except of CAT. These results may suggest that SA plays an important role in triggering the root antioxidant system, thereby preventing membrane damage as well as the denaturation of its components.
Asunto(s)
Antioxidantes/metabolismo , Cadmio/toxicidad , Lino/efectos de los fármacos , Lino/metabolismo , Ácido Salicílico/farmacología , Catalasa/metabolismo , Permeabilidad de la Membrana Celular/efectos de los fármacos , Peróxido de Hidrógeno/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Peróxidos Lipídicos/metabolismo , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Peroxidasas/metabolismo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
Soils from the alluvial flats of the Turia River, Valencia, Spain, which were highly contaminated by decades of industrial activity, were surveyed for native plant species that could be candidates useful in phytoremediation. Concentrations of heavy metals and arsenic (As) in soils reached 25,000 mg Kg(-1) Pb, 12,000 mg Kg(-1) Zn, 70 mg Kg(-1) Cd, and 13500 mg Kg(-1) As. The predominant vegetation was collected and species identified. Soil samples and the corresponding plant shoots were analyzed to determine the amount of As accumulated by the various plant species. Several were able to tolerate more than 1000 mg Kg(-1) As in the soil. Bassia scoparia (Chenopodiaceae) survive in soil with 8375 mg Kg(-1) As. Arsenic accumulation in shoots of the various plant species investigated ranged from 0.1 to 107 mg Kg(-1) dw. Bassia scoparia (Chenopodiaceae), Inula viscosa (Asteraceae), Solanum nigrum (Solanaceae), and Hirschfeldia incana (Brassicaceae) had the highest values for As accumulation.
Asunto(s)
Arsénico/metabolismo , Plantas/metabolismo , Contaminantes del Suelo/metabolismo , Biodegradación Ambiental , Residuos Industriales , Ríos , Contaminantes del Suelo/química , España , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/metabolismoRESUMEN
Quantitative trait loci (QTLs) contributing to yellow seed colour and acid detergent fibre (ADF) were localized and compared in 3 mapping populations developed from 2 crosses (designated 'YE1' and 'YE2') between 2 distinct sources of true-breeding yellow-seeded oilseed rape (Brassica napus) and 2 different black-seeded genotypes. A clear correlation was observed between seed colour and ADF content in both crosses. In all 3 populations, a major QTL, with a large effect on both seed colour and ADF in multiple environments, was detected at the same position on chromosome N18. In YE1, a second minor QTL, with a small effect on seed colour but not on ADF content, was localized on chromosome N1. In YE2, no QTL was observed on N1; however, 2 minor seed-colour loci were localized to N15 and N5. A second major QTL for ADF was localized in YE1 on N13; in YE2, no other QTLs for ADF were detected. Combined QTL and segregation data for seed colour and ADF content in the different populations suggest that a partially dominant B. napus gene for seed colour on N18 contributes to a reduction in fibre content in different yellow-seeded B. napus genotypes. The other QTLs that were identified appear to represent different genes in the 2 yellow-seeded rapeseed sources, which, in each case, affect only fibre content or seed colour, respectively. Potential candidate genes and implications for marker-assisted breeding of oilseed rape with reduced seed dietary fibre content are discussed.
Asunto(s)
Brassica napus/genética , Cruzamientos Genéticos , Genes Dominantes , Pigmentación/genética , Proteínas de Plantas/análisis , Proteínas de Plantas/genética , Sitios de Carácter Cuantitativo , Brassica napus/química , Mapeo Cromosómico , Cromosomas de las Plantas , Fibras de la Dieta/análisis , Repeticiones de Minisatélite , Semillas/genéticaRESUMEN
From a number of wild plant species growing on soils highly contaminated by heavy metals in Eastern Spain, Nicotiana glauca R. Graham (shrub tobacco) was selected for biotechnological modification, because it showed the most appropriate properties for phytoremediation. This plant has a wide geographic distribution, is fast-growing with a high biomass, and is repulsive to herbivores. Following Agrobacterium mediated transformation, the induction and overexpression of a wheat gene encoding phytochelatin synthase (TaPCS1) in this particular plant greatly increased its tolerance to metals such as Pb and Cd, developing seedling roots 160% longer than wild type plants. In addition, seedlings of transformed plants grown in mining soils containing high levels of Pb (1572 ppm) accumulated double concentration of this heavy metal than wild type. These results indicate that the transformed N. glauca represents a highly promising new tool for use in phytoremediation efforts.