Suchergebnisse

© 2014 Elsevier Ltd. Type III peroxidase (EC 1.11.1.7) (POX) is the enzyme direct responsible of the 132 OH chlorophyll formation on oxidative catabolism of chlorophylls (chls). Despite the higher content of oxidized derivatives of chlorophylls (ox-chls) in fruits of the Arbequina variety compared to Hojiblanca, the evolution of total chlorophyll oxidative peroxidase activity (POX-chl) showed that this activity levels were higher in fruits of Hojiblanca compared with Arbequina variety. Subsequently, a deepened study on the subcellular distribution of POX-chl activity from mesocarp and epicarp cells of olive fruit of both varieties was made, finding that the POX-chl activity located in thylakoid fraction (the only fraction in direct contact with chls in vivo) was in Arbequina fruits higher than in Hojiblanca ones and involved more than 50% of the membranous POX-Chl activity. It has been demonstrated also that the evolution of the POX-chl activity in thylakoid membranes enriched fraction throughout the whole life cycle was parallel with the formation and accumulation of ox-chls in olive fruits. Data allowed to conclude that the formation of ox-chls during the chl catabolism is mediated by a POX-chl activity localized in thylakoid fraction and allow to hypothesize that the high percentage of POX activity found in the soluble cell fraction, estimated at 99.8%, may be involved in the loss of pigmentation by oxidation occurring during fruit processing for obtaining olive oil. ; This work was supported by the Comision Interministerial de Ciencia y Tecnología (CICYT-EU, Spanish and European Governments) under research project AGL 2007-66139-C02-01/ALI and by the Junta de Andalucía in the Project AGR 2010-6271. We thank Sergio Alcañíz for technical assistance and "Cortijo Carcahueso" (Aznalcóllar, Sevilla, Spain) and Hacienda Guzmán (ACEITES DEL SUR-COOSUR S.A.) for supplying samples. ; Peer Reviewed

Background Olive tree (Olea europaea L. subsp. europaea, Oleaceae) has been the most emblematic perennial crop for Mediterranean countries since its domestication around 6000 years ago in the Levant. Two taxonomic varieties are currently recognized: cultivated (var. europaea) and wild (var. sylvestris) trees. However, it remains unclear whether olive cultivars derive from a single initial domestication event followed by secondary diversification, or whether cultivated lineages are the result of more than a single, independent primary domestication event. To shed light into the recent evolution and domestication of the olive tree, here we analyze a group of newly sequenced and available genomes using a phylogenomics and population genomics framework. Results We improved the assembly and annotation of the reference genome, newly sequenced the genomes of twelve individuals: ten var. europaea, one var. sylvestris, and one outgroup taxon (subsp. cuspidata)—and assembled a dataset comprising whole genome data from 46 var. europaea and 10 var. sylvestris. Phylogenomic and population structure analyses support a continuous process of olive tree domestication, involving a major domestication event, followed by recurrent independent genetic admixture events with wild populations across the Mediterranean Basin. Cultivated olives exhibit only slightly lower levels of genetic diversity than wild forms, which can be partially explained by the occurrence of a mild population bottleneck 3000–14,000 years ago during the primary domestication period, followed by recurrent introgression from wild populations. Genes associated with stress response and developmental processes were positively selected in cultivars, but we did not find evidence that genes involved in fruit size or oil content were under positive selection. This suggests that complex selective processes other than directional selection of a few genes are in place. Conclusions Altogether, our results suggest that a primary domestication area in the eastern Mediterranean basin was followed by numerous secondary events across most countries of southern Europe and northern Africa, often involving genetic admixture with genetically rich wild populations, particularly from the western Mediterranean Basin. ; This research has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 724173; RETVOLUTION)". IJ was supported in part by a grant from the Peruvian Ministry of Education: "Beca Presidente de la República" (2013-III). ; Postprint (published version)

Background: Olive tree (Olea europaea L. subsp. europaea, Oleaceae) has been the most emblematic perennial crop for Mediterranean countries since its domestication around 6000 years ago in the Levant. Two taxonomic varieties are currently recognized: cultivated (var. europaea) and wild (var. sylvestris) trees. However, it remains unclear whether olive cultivars derive from a single initial domestication event followed by secondary diversification, or whether cultivated lineages are the result of more than a single, independent primary domestication event. To shed light into the recent evolution and domestication of the olive tree, here we analyze a group of newly sequenced and available genomes using a phylogenomics and population genomics framework. Results: We improved the assembly and annotation of the reference genome, newly sequenced the genomes of twelve individuals: ten var. europaea, one var. sylvestris, and one outgroup taxon (subsp. cuspidata)-and assembled a dataset comprising whole genome data from 46 var. europaea and 10 var. sylvestris. Phylogenomic and population structure analyses support a continuous process of olive tree domestication, involving a major domestication event, followed by recurrent independent genetic admixture events with wild populations across the Mediterranean Basin. Cultivated olives exhibit only slightly lower levels of genetic diversity than wild forms, which can be partially explained by the occurrence of a mild population bottleneck 3000-14,000 years ago during the primary domestication period, followed by recurrent introgression from wild populations. Genes associated with stress response and developmental processes were positively selected in cultivars, but we did not find evidence that genes involved in fruit size or oil content were under positive selection. This suggests that complex selective processes other than directional selection of a few genes are in place. Conclusions: Altogether, our results suggest that a primary domestication area in the eastern Mediterranean basin was followed by numerous secondary events across most countries of southern Europe and northern Africa, often involving genetic admixture with genetically rich wild populations, particularly from the western Mediterranean Basin. ; This research has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 724173; RETVOLUTION)". IJ was supported in part by a grant from the Peruvian Ministry of Education: "Beca Presidente de la República" (2013-III).

In Morocco, the recovery of olive agro-industrial by-products as potential sources of high-added value substances has been underestimated so far. A comprehensive quantitative characterization of olive leaves' bioactive compounds is crucial for any attempt to change this situation and to implement the valorization concept in emerging countries. Thus, the phenolic fraction of olive leaves of 11 varieties ('Arbequina', 'Hojiblanca', 'Frantoio', 'Koroneiki', 'Lechín', 'Lucque', 'Manzanilla', 'Picholine de Languedoc', 'Picholine Marocaine', 'Picual' and 'Verdal'), cultivated in the Moroccan Meknès region, was investigated. Thirty eight phenolic or related compounds (including 16 secoiridoids, nine flavonoids in their aglycone form, seven flavonoids in glycosylated form, four simple phenols, one phenolic acid and one lignan) were determined in a total of 55 samples by using ultrasonic-assisted extraction and liquid chromatography coupled to electrospray ionization-ion trap mass spectrometry (LC-ESI-IT MS). Very remarkable quantitative differences were observed among the profiles of the studied cultivars. 'Picholine Marocaine' variety exhibited the highest total phenolic content (around 44 g/kg dry weight (DW)), and logically showed the highest concentration in terms of various individual compounds. In addition, chemometrics (principal components analysis (PCA) and stepwise-linear discriminant analysis (s-LDA)) were applied to the quantitative phenolic compound data, allowing good discrimination of the selected samples according to their varietal origin. ; This research was funded by the Spanish Government (Ministerio de Educación, Cultura y Deporte) with a FPU fellowship (FPU13/06438), the Vice-Rector's Office for International Relations and Development Cooperation of the University of Granada, and the contract 30C0366700 (OTRI, University of Granada, Spain)

In olive groves, vegetation ground cover (VGC) plays an important ecological role. The EU Common Agricultural Policy, through cross-compliance, acknowledges the importance of this factor, but, to determine the real impact of VGC, it must first be quantified. Accordingly, in the present study, eleven vegetation indices (VIs) were applied to quantify the density of VGC in olive groves (Olea europaea L.), according to high spatial resolution (10&ndash ; 12 cm) multispectral images obtained by an unmanned aerial vehicle (UAV). The fieldwork was conducted in early spring, in a Mediterranean mountain olive grove in southern Spain presenting various VGC densities. A five-step method was applied: (1) generate image mosaics using UAV technology ; (2) apply the VIs ; (3) quantify VGC density by means of sampling plots (ground-truth) ; (4) calculate the mean reflectance of the spectral bands and of the VIs in each sampling plot ; and (5) quantify VGC density according to the VIs. The most sensitive index was IRVI, which accounted for 82% (p < ; 0.001) of the variability of VGC density. The capability of the VIs to differentiate VGC densities increased in line with the cover interval range. RVI most accurately distinguished VGC densities > ; 80% in a cover interval range of 10% (p < ; 0.001), while IRVI was most accurate for VGC densities < ; 30% in a cover interval range of 15% (p < ; 0.01). IRVI, NRVI, NDVI, GNDVI and SAVI differentiated the complete series of VGC densities when the cover interval range was 30% (p < ; 0.001 and p < ; 0.05).