Molecular characterization of marine fungi isolated from Manila Bay, Philippines.

Abstract

Marine fungi play vital roles in marine ecosystems. They are the main decomposers in the ecosystem, major component in the food chain, pollution indicators and primarily involved in nutrient cycling. However, inadequate information is available about marine fungi especially those thriving in Manila Bay, Philippines. This thesis aims to molecularly characterize using the 18s rRNA sequences the marine fungi present in Manila Bay, which were previously morphologically identified by Duenas and Roderno (2013). To do this, 3 major activities were performed, namely, DNA optimization, DNA amplification and sequence analysis. Xanthogenate extraction protocol was found to be effective for Aspergillus sp. (UPM001), Aspergillus sp. (UPM002), Aspergillus sp. (UPM003) and Yeast (Non-Candida) species (UPM006). CTAB extraction protocol was found to be effective for Penicillium sp. (UPM004) and Trichoderma sp (UPM005). The marine fungi were phylogenetically identified using reference sequences present in the NCBI GenBank database. Aspergillus sp. (UPM001), previously identified as Aspergillus flavus, was shown to be a relative of Aspergillus sojae. Aspergillus sp. (UPM002), previously identified as Aspergillus fumigatus, was shown to be a distinct species relative of Aspergillus fumigatus. Aspergillus sp. (UPM003), previously identified as a species belonging to the Aspergillus genera, was shown to be a relative of Talaromyces flavus. Penicillium sp. (UPM004), previously identified as Penicillium sp., was shown be a relative of Eupenicillium crustaceum and Penicillium nodositatum. Trichoderma sp. (UPM005), previously identified as Trichoderma sp, was identified to be Trichoderma viridae. Yeast (Non-Candida) (UPM006), previously identified as a Non-Candida species, was shown to be a relative of Kodamaea ohmeri. This study shows that molecular characterization is a more accurate identification tool for microorganisms.