Yeasts are unicellular microorganisms that belong to the kingdom of fungi. Yeasts are found in a diverse range of habitats, including soil, sugar-rich surfaces on the fruit and flowers of plants, and on the surface of plants and animals. Yeast plays an important role in soil by participating in nutrient cycles and
mineralization processes. In contrast to the various studies investigating soil yeasts in Western countries, there is a dearth of research investigating soil yeasts in Africa and the Middle East. In these projects, we
collected 493 soil samples from nine different geographical locations in Cameroon, and 562 soil samples from six geographical locations in Saudi Arabia. I identified yeast isolates by using the culture-based method and the fungal barcode sequence at the ITS region. In addition, the yeast species were analyzed
using PCR- fingerprinting to investigate the genetic variation among strains within the same species. In sum, we have isolated and identified a total of 110 yeast isolates from Cameroon as well as a total of 114 yeast isolates from Saudi Arabia. Our results showed that soil samples from different regions in Cameroon had different yeast colonization (0%-56%), with the highest found in northwest Cameroon. The Saudi
Arabian yeast isolation was different from those in Cameroon, with less diversity; the isolation rate ranged from 0.7 to 40.2 %, with the highest found in western Saudi Arabia. PCR-fingerprinting results suggested
that yeast migration was common among the geographic regions within each country. However, local climatic conditions can significantly impact yeast diversity at the local and continental levels. / Thesis / Master of Science (MSc) / Yeasts are single-celled microorganisms that are widely dispersed in a wide variety of natural and human-related habitats such as plant leaves, flowers, fruits, water, and soil. Yeast is probably one of the earliest domesticated organisms; people have used yeast for fermentation and baking through much of the recorded human history. My project focused on studying yeast diversity in two geographically distinct countries, Cameroon and Saudi Arabia, in the context of environmental factors such as climate conditions and pH. I identified yeast present in soil samples morphologically, sequenced them at the ITS locus, and determined
the genetic variation among isolates within individual yeast species using PCR fingerprinting. The analysis revealed differences in yeast species distribution and in yeast genotypic diversity among the analyzed geographic regions. These results suggest that Cameroon and Saudi Arabia contain significant novel yeast
diversity.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22757 |
| Date | January 2018 |
| Creators | Aljohani, Renad |
| Contributors | Xu, Jianping, Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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