Molecular characterization of a scytonemin-producing microbial mat from Canary Islands

Abstract

Microbial mats are multilayered microbial communities usually growing in environments with extreme conditions, such as intertidal flats, hypersaline ponds or hot springs. Cyanobacteria form the top layer of microbial mats where they produce and accumulate the extracellular pigment, scytonemin, to protect themselves from UV irradiation. To date, the intertidal microbial mat community, particularly the scytonemin-producing cyanobacteria, from Canary Islands, has not been studied. In this work, we study the scytonemin-producing cyanobacterial community from the intertidal zone at a site in Las Palmas de Gran Canaria, by PCR amplification of scyC gene (encoding a protein involved in the biosynthesis of scytoneemin) and phylogenetic analysis using 16S rDNA gene cloning and sequencing. The scyC gene was amplified from all samples. The phylogenetic analysis of a clone library of 16S amplicons from two samples revealed that pseudanabaenacean cyanobacteria related to the genus Phormidesmis were more abundant. The presence of thhese pseudanabaenacean cyanobacteria along with other Nostocales and Chroococcales was confirmed through booth optical and electron microscope observations. Also, pure scytonemin and reduced scytonemin were isolated from these samples and both compounds were identified by 1H-NNMR and MS.