Identificación y caracterización molecular de cianobacterias tropicales de los géneros Nostoc, Calothrix, TolypothrixyScytonema (Nostocales: Nostocaceae), con posible potencial biotecnológico

Abstract

Las cianobacterias son procariotas fotoautótrofos, morfológica y molecularmente diversas, en las cuales se han reportado avances biotecnológicos sobre fijación de nitrógeno, biorremediación y valor nutricional-farmacéutico. La identificación tradicional de cianobacterias basada en morfología puede ser imprecisa, por lo que las técnicas moleculares son una herramienta robusta para el posicionamiento taxonómico de estas cepas tropicales. Este estudio se enfoca en la identificación morfológica y caracterización molecular de cianobacterias de ambientes tropicales de Costa Rica, para perspectivas biotecnológicas futuras. Las cepas fueron cultivadas en medio BG0-11, fotografiadas en microscopio de luz y clasificadas a nivel de género. La identificación molecular se llevó a cabo utilizando cebadores del gen ARN polimerasa ADN-dependiente (rpoC1) y la subunidad pequeña ARN ribosomal (16S ARNr). Seguidamente, se realizó un análisis de posicionamiento filogenético mediante alineamiento múltiple con MAFFTv.7 y máxima- verosimilitud con raxMLGUI. Basados en características fenotípicas, se identificaron cuatro géneros de cianobacterias Nostocales: Calothrix sp., Tolypothrix sp., Scytonema sp. y Nostoc sp. Los géneros identificados son conocidos por su capacidad de fijación de nitrógeno y potencial nutricional, farmacológico e industrial. Con una identificación exitosa de cianobacterias de ambientes tropicales, es posible continuar con más estudios de sus propiedades biotecnológicas y evaluar su potencial, con perspectivas futuras de aplicación y conservación de la biodiversidad.

Identification and molecular characterization of tropical cyanobacteria of the genus Nostoc, Calothrix, Tolypothrix and Scytonema (Nostocales: Nostocaceae), with possible biotechnological potential. Cyanobacteria or “Blue-Green” algae comprise a diverse cluster of prokaryotic photoautotrophs that share a high morphological and molecular abundance. Biotechnological advances on nitrogen fixation, bioremediation, pharmaceutical and nutritional value have been developed. Traditional identification based on morphology has been the most common applied technique, but it may be inaccurate because of the phenotypic plasticity that those organisms present. For this reason, molecular techniques had become robust tools for taxonomic positioning of tropical cyanobacterial isolates, associated with morphology identification. This study focuses on the morphological identification and molecular characterization of cyanobacteria isolated in different tropical environments of Costa Rica, for biotechnological prospects. Strains were grown in BG0-11 media, photographed under light microscope and classified at genera level. Molecular identification was carried by PCR and sequencing using DNA-dependent RNA polymerase (rpoC1) and small-subunit ribosomal RNA (16S rRNA) gen primers. Subsequently, a phylogenetic positioning analysis was performed by MAFFTv.7 alignment and maximum likelihood by raxMLGUI. Based on phenotypic characteristics, four genera of Nostocales were identified: Calothrix sp., Tolypothrix sp., Scytonema sp. and Nostoc sp. Molecular analysis shows a taxonomic grouping that is consistent with the observed morphology, with the 16S rDNA gene yielding robust and stable results. The identified genera are known for their nitrogen fixation capability: Nostoc and Calothrix have been used in maintaining fertility and soil recovering studies. Nostoc is known for its nutritional properties and biofuel production; a characteristic shared by Tolypothrix as well. The last genera; Scytonema, it is known for its pharmacological properties. With the successful identification of cyanobacteria strains isolated from tropical environments, it is possible to continue the study of genes responsible for properties of biotechnological interest and to evaluate their potential, with future perspectives of application and biodiversity conservation.