Publications by authors named "Ana V Lasa"

6 Publications

  • Page 1 of 1

Involvement of the metabolically active bacteria in the organic matter degradation during olive mill waste composting.

Sci Total Environ 2021 Oct 25;789:147975. Epub 2021 May 25.

Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ), Agencia Estatal CSIC, c/ Profesor Albareda, 1, 18008 Granada, Spain.

RNA-based high-throughput sequencing is a valuable tool in the discernment of the implication of metabolically active bacteria during composting. In this study, "alperujo" composting was used as microbial model for the elucidation of structure-function relationships with physicochemical transformation of the organic matter. DNA and RNA, subsequently retrotranscribed into cDNA, were isolated at the mesophilic, thermophilic and maturation phases. 16S rRNA gene was amplified by quantitative PCR (qPCR) and Illumina MiSeq platform to assess bacterial abundance and diversity, respectively. The results showed that the abundance of active bacteria assessed by qPCR was maximum at thermophilic phase, which confirm it as the most active stage of the process. Concerning diversity, Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the main phyla presented in composts. Concomitantly, three different behaviours were observed for bacterial dynamics: some genera decreased during the whole process meanwhile others proliferated only at thermophilic or maturation phase. Statistical correlation between physicochemical transformations of the organic matter and bacterial diversity revealed bacterial specialisation. This result indicated that specific groups of bacteria were only involved in the organic matter degradation during bio-oxidative phase or humification at maturation. Metabolic functions predictions confirmed that active bacteria were mainly involved in carbon (C) and nitrogen (N) cycles transformations, and pathogen reduction.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147975DOI Listing
October 2021

Comparative study of neighboring Holm oak and olive trees-belowground microbial communities subjected to different soil management.

PLoS One 2020 11;15(8):e0236796. Epub 2020 Aug 11.

Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain.

It is well-known that different plant species, and even plant varieties, promote different assemblages of the microbial communities associated with them. Here, we investigate how microbial communities (bacteria and fungi) undergo changes within the influence of woody plants (two olive cultivars, one tolerant and another susceptible to the soilborne fungal pathogen Verticillium dahliae, plus wild Holm oak) grown in the same soil but with different management (agricultural versus native). By the use of metabarcoding sequencing we determined that the native Holm oak trees rhizosphere bacterial communities were different from its bulk soil, with differences in some genera like Gp4, Gp6 and Solirubrobacter. Moreover, the agricultural management used in the olive orchard led to belowground microbiota differences with respect to the natural conditions both in bulk soils and rhizospheres. Indeed, Gemmatimonas and Fusarium were more abundant in olive orchard soils. However, agricultural management removed the differences in the microbial communities between the two olive cultivars, and these differences were minor respect to the olive bulk soil. According to our results, and at least under the agronomical conditions here examined, the composition and structure of the rhizospheric microbial communities do not seem to play a major role in olive tolerance to V. dahliae.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236796PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418964PMC
October 2020

Bacteria from the endosphere and rhizosphere of Quercus spp. use mainly cell wall-associated enzymes to decompose organic matter.

PLoS One 2019 25;14(3):e0214422. Epub 2019 Mar 25.

Departament of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain.

Due to the ability of soil bacteria to solubilize minerals, fix N2 and mobilize nutrients entrapped in the organic matter, their role in nutrient turnover and plant fitness is of high relevance in forest ecosystems. Although several authors have already studied the organic matter decomposing enzymes produced by soil and plant root-interacting bacteria, most of the works did not account for the activity of cell wall-attached enzymes. Therefore, the enzyme deployment strategy of three bacterial collections (genera Luteibacter, Pseudomonas and Arthrobacter) associated with Quercus spp. roots was investigated by exploring both cell-bound and freely-released hydrolytic enzymes. We also studied the potential of these bacterial collections to produce enzymes involved in the transformation of plant and fungal biomass. Remarkably, the cell-associated enzymes accounted for the vast majority of the total activity detected among Luteibacter strains, suggesting that they could have developed a strategy to maintain the decomposition products in their vicinity, and therefore to reduce the diffusional losses of the products. The spectrum of the enzymes synthesized and the titres of activity were diverse among the three bacterial genera. While cellulolytic and hemicellulolytic enzymes were rather common among Luteibacter and Pseudomonas strains and less detected in Arthrobacter collection, the activity of lipase was widespread among all the tested strains. Our results indicate that a large fraction of the extracellular enzymatic activity is due to cell wall-attached enzymes for some bacteria, and that Quercus spp. root bacteria could contribute at different levels to carbon (C), phosphorus (P) and nitrogen (N) cycles.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214422PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6433265PMC
December 2019

Metabarcoding reveals that rhizospheric microbiota of Quercus pyrenaica is composed by a relatively small number of bacterial taxa highly abundant.

Sci Rep 2019 02 8;9(1):1695. Epub 2019 Feb 8.

Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, calle Profesor Albareda 1, 18008, Granada, Spain.

Melojo oak (Quercus pyrenaica Willd.) is a key tree species of Mediterranean forests; however, these forests show an advanced stage of deterioration in the Iberian Peninsula. Plant-associated microorganisms play an essential role improving their host's fitness, hence, a better understanding of oak rhizospheric microbiome, especially of those active members, could be the first step towards microbiome-based approaches for oak-forest improvement. Here we reported, for the first time, the diversity of total (DNA-based) and potentially active (RNA-based) bacterial communities of different melojo-oak forest formations through pyrosequencing of 16S rRNA gene amplicons. We found that potentially active bacterial communities were as rich and diverse as total bacterial communities, but different in terms of relative abundance patterns in some of the studied areas. Both core microbiomes were dominated by a relatively small percentage of OTUs, most of which showed positive correlation between both libraries. However, the uncoupling between abundance (rDNA) and potential activity (rRNA) for some taxa suggests that the most abundant taxa are not always the most active, and that low-abundance OTUs may have a strong influence on oak's rhizospheric ecology. Thus, measurement of rRNA:rDNA ratio could be helpful in identifying major players for the development of bacterial bioinoculants.
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http://dx.doi.org/10.1038/s41598-018-38123-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6368570PMC
February 2019

Whole-Genome Sequences of Two Arthrobacter Strains Isolated from a Holm Oak Rhizosphere Affected by Wildfire.

Genome Announc 2018 Mar 15;6(11). Epub 2018 Mar 15.

Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain

We report here the draft genome sequences of two strains isolated from a holm oak forest affected by wildfire. Both strains were shown to act as plant growth promoters, with AFG20 being a member of the most abundant group found in this soil and AFG7.2 being the strain with the highest indole-3-acetic acid production level.
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http://dx.doi.org/10.1128/genomeA.00071-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5854774PMC
March 2018

Analysis of rhizobial endosymbionts of Vicia, Lathyrus and Trifolium species used to maintain mountain firewalls in Sierra Nevada National Park (South Spain).

Syst Appl Microbiol 2017 Mar 28;40(2):92-101. Epub 2016 Dec 28.

Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.

Forest fires lead to the annual disappearance of many natural formations that require the creation of firewall areas. They can be maintained by enriching their pastures with attractive plants for grazing livestock, mainly legumes, which have a high protein content and low dependence on N fertilizers due to their ability to establish nitrogen-fixing symbiosis with rhizobia. In this study, the rhizobia isolated from the nodules of six legumes from the genera Vicia, Lathyrus and Trifolium were analysed in a firewall zone established in Lanjarón (Granada) close to the Sierra Nevada National Park (Spain). The results showed a high genetic diversity of the isolated strains that had 3, 16, 14 and 13 different types of rrs, recA, atpD and glnII genes, respectively. All strains were phylogenetically close to the species from the Rhizobium leguminosarum group, although they were not identified as any of them. The isolated strains belonged to the symbiovars viciae and trifolii but high phylogenetic diversity was found within both symbiovars, since there were 16 and 14 nodC gene types, respectively. Some of these strains clustered with strains isolated in other countries and continents, but others formed atpD, recA, glnII and nodC clusters and lineages only found to date in this study.
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http://dx.doi.org/10.1016/j.syapm.2016.11.008DOI Listing
March 2017
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