Díaz-Muñoz, Greetchen.

Profile Picture

Filters

20061
Reset filters

Settings

Citations

Publication Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Publication
    Fungal diversity present at a hypersaline environment in Cabo Rojo, Puerto Rico, determined by characterization of isolates and analysis of environmental rRNA genes clones libraries
    (2006) Díaz-Muñoz, Greetchen.; Montalvo-Rodríguez, Rafael R.; College of Arts and Sciences - Sciences; Santos Flores, Carlos; Ríos Velázquez, Carlos; Betancourt López, Carlos; Department of Biology; Zapata, Mildred
    Solar salterns are a thalassohaline environment where sea water is evaporated to obtain salt for commercial purposes. The prokaryotic diversity on these places has been extensively studied world wide. However, there are few reports that focus their attention on the fungal diversity present on this extreme environment. The main objective of this research project was to isolate and characterize halotolerant filamentous fungi from the salterns of Cabo Rojo, Puerto Rico. To determine the occurrence of fungi in these solar salterns, water samples were filtered, plated on three different media (Sehgal and Gibbons, malt extract, and potato dextrose) each at 15% NaCl and incubated at 29ºC. Selected isolates were characterized using light and scanning electron microscopy, and some physiological properties like secondary metabolite profiles, optimal NaCl concentration, pH and temperature were determined. Molecular analysis using RFLP patterns of a PCR amplicon containing the 5.8S rDNA and ITS1-ITS2 regions was also used to classify the isolates into groups. Taxonomic results indicated that several groups of fungi can be obtained from this hostile environment. A total of eight genera and seventeen species were reported. These include the filamentous fungi Alternaria sp. Aspergillus elegans, A. sydowii, A. terreus, A. versicolor, A oryzae, A. japonicus, A. niger aggregate, Cladosporium cladosporioides, C. sphaerospermum, Eurotium amstelodami, Penicillium chrysogenum, P. expansum, Stemphylium sp. and an unknown species. The dimorphic yeast, Hortaea werneckii, was also isolated at a high frequency. Many isolates tolerated NaCl concentrations up to 30% and showed a wide range of growth temperatures and pH. The ability of these isolates to grow at high salt concentrations might indicate that they are part of the biological diversity of the saltern. The fungal diversity was also analyzed by non-culture dependent methods like 18S rDNA clone libraries. The amplification of fungal DNA was very difficult to achieve due to the complexity of the saltern community. However, after protocol optimization many clones were obtained and an in silico analysis was performed. Environmental sequences belonging to the genus Aspergillus were the most frequent Operational Taxonomic Unit (OTU), but other ascomycetes and basidiomycetes OTUs were also obtained. The combination of morphological, physiological and molecular approaches was very useful to describe the fungal community at the solar salterns of Cabo Rojo. This survey represents one of the first approaches to study fungal diversity on extreme environments in the Caribbean.