Distribution of yeasts in the Arabian Gulf surrounding Qatar

The Arabian Gulf surrounding Qatar is distinct from other marine ecosystems due to its high salinity (39-57 psu) and extreme water temperature fluctuations (15-39°C). Furthermore in the last decade, Qatar has been witnessing an industrial boom as well as extensive infrastructure construction activities. During the first year of a 3-year study, we investigated the diversity of marine yeasts in Qatar. Water samples were collected during two seasons, from 14 different sites along the coastal waters of the Arabian Gulf surrounding Qatar. Yeast species were isolated and identified by sequence analyses of the internal transcribed spacers (ITS1/ITS2) and the D1/D2 domains of the large subunit (LSU) of the ribosomal DNA (rDNA). A total of 360 yeast isolates belonging to 37 genera of Ascomycetes and Basidiomycetes were identified during the two sampling campaigns. Species distribution depicted seasonal and geographical differences. Candida spp. (24%), Rhodotorula spp. (16 %), Kondoa aeria (8%), Aureobasidium spp. (7%), and Hortaea spp. (7%) were among the most frequently identified yeast species. High prevalence of Kondoa spp. (34%), Knufia spp. (24%), and Hypocrea spp. (13%) was observed during summer season, whereas Debaryomyces spp. (37%), Clavispora spp. (23%), Issatchenkia spp. (17%) were the most common species during the winter season. The highest number of yeast isolates was recovered from sites impacted by land-based activities, especially fishing harbors along the Eastern coast of Qatar. This report is the first study on the distribution of yeasts from the marine environment surrounding Qatar.