Dataset Information

High Culturable Bacterial Diversity From a European Desert: The Tabernas Desert.

ABSTRACT: One of the most diverse ecological niches for microbial bioprospecting is soil, including that of drylands. Drylands are one of the most abundant biomes on Earth, but extreme cases, such as deserts, are considered very rare in Europe. The so-called Tabernas Desert is one of the few examples of a desert area in continental Europe, and although some microbial studies have been performed on this region, a comprehensive strategy to maximize the isolation of environmental bacteria has not been conducted to date. We report here a culturomics approach to study the bacterial diversity of this dryland by using a simple strategy consisting of combining different media, using serial dilutions of the nutrients, and using extended incubation times. With this strategy, we were able to set a large (254 strains) collection of bacteria, the majority of which (93%) were identified through 16S ribosomal RNA (rRNA) gene amplification and sequencing. A significant fraction of the collection consisted of Actinobacteria and Proteobacteria, as well as Firmicutes strains. Among the 254 isolates, 37 different genera were represented, and a high number of possible new taxa were identified (31%), of which, three new Kineococcus species. Moreover, 5 out of the 13 genera represented by one isolate were also possible new species. Specifically, the sequences of 80 isolates held a percentage of identity below the 98.7% threshold considered for potentially new species. These strains belonged to 20 genera. Our results reveal a clear link between medium dilution and isolation of new species, highlight the unexploited bacterial biodiversity of the Tabernas Desert, and evidence the potential of simple strategies to yield surprisingly large numbers of diverse, previously unreported, bacterial strains and species.

SUBMITTER: Molina-Menor E

PROVIDER: S-EPMC7821382 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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High Culturable Bacterial Diversity From a European Desert: The Tabernas Desert.

Molina-Menor Esther E Gimeno-Valero Helena H Pascual Javier J Peretó Juli J Porcar Manuel M

Frontiers in microbiology 20210108

One of the most diverse ecological niches for microbial bioprospecting is soil, including that of drylands. Drylands are one of the most abundant biomes on Earth, but extreme cases, such as deserts, are considered very rare in Europe. The so-called Tabernas Desert is one of the few examples of a desert area in continental Europe, and although some microbial studies have been performed on this region, a comprehensive strategy to maximize the isolation of environmental bacteria has not been conduc ...[more]

PMID: 33488536

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Project description:The phylum Actinobacteria constitutes one of the largest and anciently divergent phyla within the Bacteria domain. Actinobacterial diversity has been thoroughly researched in various environments due to its unique biotechnological potential. Such studies have focused mostly on soil communities, but more recently marine and extreme environments have also been explored, finding rare taxa and demonstrating dispersal limitation and biogeographic patterns for Streptomyces. To test the distribution of Actinobacteria populations on a small scale, we chose the extremely oligotrophic and biodiverse Cuatro Cienegas Basin (CCB), an endangered oasis in the Chihuahuan desert to assess the diversity and uniqueness of Actinobacteria in the Churince System with a culture-dependent approach over a period of three years, using nine selective media. The 16S rDNA of putative Actinobacteria were sequenced using both bacteria universal and phylum-specific primer pairs. Phylogenetic reconstructions were performed to analyze OTUs clustering and taxonomic identification of the isolates in an evolutionary context, using validated type species of Streptomyces from previously phylogenies as a reference. Rarefaction analysis for total Actinobacteria and for Streptomyces isolates were performed to estimate species' richness in the intermediate lagoon (IL) in the oligotrophic Churince system. A total of 350 morphologically and nutritionally diverse isolates were successfully cultured and characterized as members of the Phylum Actinobacteria. A total of 105 from the total isolates were successfully subcultured, processed for DNA extraction and 16S-rDNA sequenced. All strains belong to the order Actinomycetales, encompassing 11 genera of Actinobacteria; the genus Streptomyces was found to be the most abundant taxa in all the media tested throughout the 3-year sampling period. Phylogenetic analysis of our isolates and another 667 reference strains of the family Streptomycetaceae shows that our isolation effort produced 38 unique OTUs in six new monophyletic clades. This high biodiversity and uniqueness of Actinobacteria in an extreme oligotrophic environment, which has previously been reported for its diversity and endemicity, is a suggestive sign of microbial biogeography of Actinobacteria and it also represents an invaluable source of biological material for future ecological and bioprospecting studies.

Project description:BACKGROUND AND OBJECTIVES:Lactic acid bacteria (LAB) play important roles in processing of Sayur Asin (spontaneously fermented mustard). Unfortunately, information about LAB in Indonesian Sayur Asin, prepared by traditional manufactures which is important as baseline data for maintenance of food quality and safety, is unclear. The aim of this study was to describe the diversity and distribution of culturable lactic acid bacteria in Sayur Asin of Indonesia. MATERIALS AND METHODS:Four Sayur Asin samples (fermentation liquor and fermented mustard) were collected at harvesting times (3-7 days after fermentation) from two traditional manufactures in Tulung Agung (TA) and Kediri (KDR), East Java provinces, Indonesia. LAB strains were isolated by using MRS agar method supplemented with 1% CaCO 3 and characterized morphologically. Identification of the strains was performed basedon 16S rDNA analysis and the phylogenetic tree was drawn to understand the phylogenetic relationship of the collected strains. RESULTS:Different profiles were detected in total count of the plates, salinity and pH of fermenting liquor of Sayur Asin in TA and KDR provinces. A total of 172 LAB isolates were successfully isolated and identified based on their 16S rDNA sequences. Phylogenetic analysis of 27 representative LAB strains from Sayur Asin showed that these strains belonged to 5 distinct species namely Lactobacilus farciminis (N=32), L. fermentum (N=4), L. namurensis (N=15), L. plantarum (N=118) and L. parafarraginis (N=1). Strains D5-S-2013 and B4-S-2013 showed a close phylogenetic relationship with L. composti and L. paralimentarius, respectively where as the sequence had slightly lower similarity of lower than 99%, suggesting that they may be classified into novel species and need further investigation due to exhibition of significant differences in their nucleotide sequences. Lactobacillus plantarum was found being dominant in all sayur asin samples. CONCLUSION:Lactobacilli were recognized as the major group of lactic acid bacteria in Sayur Asin including 5 known and 2 novel candidate species. The distribution of LAB species was associated with the manufactures where Sayur Asin is produced.

Dataset Information

High Culturable Bacterial Diversity From a European Desert: The Tabernas Desert.

Publications

High Culturable Bacterial Diversity From a European Desert: The Tabernas Desert.

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