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Dive into the research topics where Magdalena Guardiola is active.

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Featured researches published by Magdalena Guardiola.


PLOS ONE | 2015

Deep-Sea, Deep-Sequencing: Metabarcoding Extracellular DNA from Sediments of Marine Canyons

Magdalena Guardiola; María Jesús Uriz; Pierre Taberlet; Eric Coissac; Owen S. Wangensteen; Xavier Turon

Marine sediments are home to one of the richest species pools on Earth, but logistics and a dearth of taxonomic work-force hinders the knowledge of their biodiversity. We characterized α- and β-diversity of deep-sea assemblages from submarine canyons in the western Mediterranean using an environmental DNA metabarcoding. We used a new primer set targeting a short eukaryotic 18S sequence (ca. 110 bp). We applied a protocol designed to obtain extractions enriched in extracellular DNA from replicated sediment corers. With this strategy we captured information from DNA (local or deposited from the water column) that persists adsorbed to inorganic particles and buffered short-term spatial and temporal heterogeneity. We analysed replicated samples from 20 localities including 2 deep-sea canyons, 1 shallower canal, and two open slopes (depth range 100–2,250 m). We identified 1,629 MOTUs, among which the dominant groups were Metazoa (with representatives of 19 phyla), Alveolata, Stramenopiles, and Rhizaria. There was a marked small-scale heterogeneity as shown by differences in replicates within corers and within localities. The spatial variability between canyons was significant, as was the depth component in one of the canyons where it was tested. Likewise, the composition of the first layer (1 cm) of sediment was significantly different from deeper layers. We found that qualitative (presence-absence) and quantitative (relative number of reads) data showed consistent trends of differentiation between samples and geographic areas. The subset of exclusively benthic MOTUs showed similar patterns of β-diversity and community structure as the whole dataset. Separate analyses of the main metazoan phyla (in number of MOTUs) showed some differences in distribution attributable to different lifestyles. Our results highlight the differentiation that can be found even between geographically close assemblages, and sets the ground for future monitoring and conservation efforts on these bottoms of ecological and economic importance.


PeerJ | 2016

Spatio-temporal monitoring of deep-sea communities using metabarcoding of sediment DNA and RNA

Magdalena Guardiola; Owen S. Wangensteen; Pierre Taberlet; Eric Coissac; María Jesús Uriz; Xavier Turon

We assessed spatio-temporal patterns of diversity in deep-sea sediment communities using metabarcoding. We chose a recently developed eukaryotic marker based on the v7 region of the 18S rRNA gene. Our study was performed in a submarine canyon and its adjacent slope in the Northwestern Mediterranean Sea, sampled along a depth gradient at two different seasons. We found a total of 5,569 molecular operational taxonomic units (MOTUs), dominated by Metazoa, Alveolata and Rhizaria. Among metazoans, Nematoda, Arthropoda and Annelida were the most diverse. We found a marked heterogeneity at all scales, with important differences between layers of sediment and significant changes in community composition with zone (canyon vs slope), depth, and season. We compared the information obtained from metabarcoding DNA and RNA and found more total MOTUs and more MOTUs per sample with DNA (ca. 20% and 40% increase, respectively). Both datasets showed overall similar spatial trends, but most groups had higher MOTU richness with the DNA template, while others, such as nematodes, were more diverse in the RNA dataset. We provide metabarcoding protocols and guidelines for biomonitoring of these key communities in order to generate information applicable to management efforts.


PeerJ | 2018

DNA metabarcoding of littoral hard-bottom communities: high diversity and database gaps revealed by two molecular markers

Owen S. Wangensteen; Creu Palacín; Magdalena Guardiola; Xavier Turon

Biodiversity assessment of marine hard-bottom communities is hindered by the high diversity and size-ranges of the organisms present. We developed a DNA metabarcoding protocol for biodiversity characterization of structurally complex natural marine hard-bottom communities. We used two molecular markers: the “Leray fragment” of mitochondrial cytochrome c oxidase (COI), for which a novel primer set was developed, and the V7 region of the nuclear small subunit ribosomal RNA (18S). Eight different shallow marine littoral communities from two National Parks in Spain (one in the Atlantic Ocean and another in the Mediterranean Sea) were studied. Samples were sieved into three size fractions from where DNA was extracted separately. Bayesian clustering was used for delimiting molecular operational taxonomic units (MOTUs) and custom reference databases were constructed for taxonomic assignment. Despite applying stringent filters, we found high values for MOTU richness (2,510 and 9,679 MOTUs with 18S and COI, respectively), suggesting that these communities host a large amount of yet undescribed eukaryotic biodiversity. Significant gaps are still found in sequence reference databases, which currently prevent the complete taxonomic assignment of the detected sequences. In our dataset, 85% of 18S MOTUs and 64% of COI MOTUs could be identified to phylum or lower taxonomic level. Nevertheless, those unassigned were mostly rare MOTUs with low numbers of reads, and assigned MOTUs comprised over 90% of the total sequence reads. The identification rate might be significantly improved in the future, as reference databases are further completed. Our results show that marine metabarcoding, currently applied mostly to plankton or sediments, can be adapted to structurally complex hard bottom samples. Thus, eukaryotic metabarcoding emerges as a robust, fast, objective and affordable method to comprehensively characterize the diversity of marine benthic communities dominated by macroscopic seaweeds and colonial or modular sessile metazoans. The 18S marker lacks species-level resolution and thus cannot be recommended to assess the detailed taxonomic composition of these communities. Our new universal primers for COI can potentially be used for biodiversity assessment with high taxonomic resolution in a wide array of marine, terrestrial or freshwater eukaryotic communities.


Conservation Genetics Resources | 2012

Characterization of nine polymorphic microsatellite loci for the calcareous sponge Paraleucilla magna Klautau et al. 2004 introduced to the Mediterranean Sea

Gemma Agell; Johanna Frotscher; Magdalena Guardiola; Marta Pascual; María Jesús Uriz

Nine polymorphic microsatellite markers are described for the calcareous sponge Paraleucilla magna. Microsatellite were isolated from a genomic library enriched for AC15, AG15, CAA10 and GATA7 repeats. The microsatellite motifs were perfect, imperfect, and compound. The polymorphism of the microsatellite loci was screened in a total of 35 individuals from two populations: western Mediterranean (Blanes, NE Spain) and Atlantic Ocean (Rio de Janeiro, Brazil). All loci were polymorphic and the number of alleles per locus ranged from 2 to 9 with an average of ca. 5 alleles per locus. Significant genetic differentiation was observed between populations. These markers have been used successfully for analysing population structure at short spatial and temporal scales, and are promising for assessing the historic pathways of the introduction of this exotic sponge, which risks to become invasive in the Mediterranean. These are the first microsatellites developed for any calcareous sponge.


PLOS ONE | 2016

Correction: Deep-Sea, Deep-Sequencing: Metabarcoding Extracellular DNA from Sediments of Marine Canyons

Magdalena Guardiola; María Jesús Uriz; Pierre Taberlet; Eric Coissac; Owen S. Wangensteen; Xavier Turon

There is an error in the third sentence of the second paragraph under the “DNA extraction, amplification and next generation sequencing” subheading of the Materials and Methods section. The correct sentence is: The primer pair was labelled 18S_allshorts (Forward 5’-TTTGTCTGSTTAATTSCG-3’ and Reverse 5’-TCACAGACCTGTTATTGC -3’).


Archive | 2015

obitools commands used in the analysis of data

Magdalena Guardiola; María Jesús Uriz; Pierre Taberlet; Eric Coissac; Owen S. Wangensteen; Xavier Turon

This file contains the obitools commands used to manipulate sequence reads, filter sequences, and assign taxonomy


Hydrobiologia | 2012

Genetic structure and differentiation at a short-time scale of the introduced calcarean sponge Paraleucilla magna to the western Mediterranean

Magdalena Guardiola; Johanna Frotscher; María Jesús Uriz


Marine Biology | 2016

High genetic diversity, phenotypic plasticity, and invasive potential of a recently introduced calcareous sponge, fast spreading across the Atlanto‑Mediterranean basin

Magdalena Guardiola; Johanna Frotscher; María-J. Uriz


Archive | 2017

Metabarcoding littoral hard-bottom communities: unexpected diversity and database gaps revealed by two molecular markers

Owen S. Wangensteen; Creu Palacín; Magdalena Guardiola; Xavier Turon


Archive | 2018

DNA metabarcoding of littoral hardbottom communities: high diversity and database gaps revealed by two molecular markers

Owen S. Wangensteen; Cruz Palacín; Magdalena Guardiola; Xavier Turon

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María Jesús Uriz

Spanish National Research Council

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Xavier Turon

University of Perpignan

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Eric Coissac

Centre national de la recherche scientifique

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Pierre Taberlet

Centre national de la recherche scientifique

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Xavier Turon

University of Perpignan

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Gemma Agell

Spanish National Research Council

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