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Qatar University (2014)

Phylogenetic Diversity of Cyanobacteria from Qatar Coastal Waters

Al-Khelaifi, Fatima Abdullah

Titre : Phylogenetic Diversity of Cyanobacteria from Qatar Coastal Waters

Auteur : Al-Khelaifi, Fatima Abdullah

Université de soutenance : Qatar University

Grade : Master thesis 2014

Résumé
Cyanobacteria represent the major microorganism phyla, being diverse and widespread group inhabiting most of the earth’s environments. The recent increase of occurrence of toxic cyanobacterial strains in the marine environment attracts attention of the scientific community and environmental managers. The deterministic factors leading to such events are under scrutiny and are closely linked to our understanding of the diversity and environmental response of these strains to environmental conditions. The extreme environment witnessed in the Arabian Gulf is likely to nurture the occurence of such harmful events. In recent times advanced molecular methodologies for the detection and genetic characterization of cyanobacteria were developed based on DNA amplification techniques. We aim in this work to better understand the diversity of the cyanobacterial natural communities found in Qatar marine environment through a genotypic characterization (phylogenetic analysis) with the objective to i. assess the local diversity, and ii. provide consistent reference for future comparative analysis, biotechnological applications and monitoring. In this study, QUCCCM strains from Qatar coastal were used to amplify fragments of the 16S rRNA gene followed by phylogenetic analysis. This methodology showed to produce accurate identification of the considered strains and analyze their evolutionary relationship. 28 taxa were identified among them 21.4% belong to the genus Geitlerinem, 25% Chroococcidiopsis, 10.7% Synechococcus, 10.7% Stanieria, 7.1% Euhalothece, 7.1% Geminocystis, 3.6% Leptolyngbya, 3.6% Oscillatoria, and 3.6% Dermocarpella. The biogeographic distribution of the strains and their potential toxicity is discussed.

Mots Clés : Arabian Gulf. Cyanobacteria. Genotypic characterization. Phylogenetic analysis. HAB. Phylogenetic diversity.

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Page publiée le 12 février 2017, mise à jour le 13 juin 2018