Morphology and molecular characterization of marine dinoflagellates (Dinophyceae)

Kon, Nyuk Fong (2012) Morphology and molecular characterization of marine dinoflagellates (Dinophyceae). [Final Year Project Report] (Unpublished)

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Abstract

There is a wide diversity of dinoflagellates inhabiting the complex nature of the marine environment. Marine dinoflagellates are potentially responsible for toxic red tides which can cause harmful effects to the surrounding ecosystem, marine life as well as human health. In this study, marine dinoflagellates were characterized based on morphology and molecular information. Field samplings were carried out at Samariang, Sarawak and clonal cultures were established. Morphological observations of cultured samples were carried out using epiflourescence microscope. The cultures established were subjected to genomic DNA isolation for molecular characterization. Gene amplification was performed to amplify the nuclear-encoded ribosomal RNA gene (rDNA). The amplicons obtained were subjected to further purification prior to DNA sequencing. In further, the nucleotide sequences obtained were analysed and used in phylogenetic reconstruction. Sequence signatures of species found were assigned for DNA barcoding. A species inventory of benthic dinoflagellates in Samariang with molecular signatures as potential DNA barcode was obtained in this study. The results of the present study showed that the Kudat isolate resembled C. malayensis with identical morphological features. The phylogenetic tree constructed for Coolia species showed that the Kudat isolate was claded together with other C. malayensis from Langkawi Island, Port Dickson and Sabah. In addition, three Prorocentrum species from Samariang and one from Kudat were identified. Their phylogenetic tree showed that they are claded into respective species clades which further supported the morphology evidence. Furthermore, one Alexandrium species was identified from Kuala Abai, Sabah. The cells had rhomboidal first apical plate (1´), wide sixth precingular plate (6´´) and posterior sulcal plate (Sp) that was wider than longer. The phylogenetic tree constructed for Alexandrium species further proved that the isolate was Alexandrium tamutum. Therefore, the morphologies and molecular data obtained were well support each other.

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