Linares, Serenella , Morris, Vernon , Chaverri, Priscila .
Comparison of DNA Extraction Methods to Assess Fungal Diversity in Saharan Dust Storms.
Saharan dust storms are massive atmospheric phenomena capable of transporting 200–300 teragrams of dust across the Atlantic Ocean every year. Although these events have been implicated in transport of human and plant pathogens across continents, little is known about the biological components of these dust masses. Previous research has primarily focused on viable organisms that can be cultured in artificial media, leaving behind an unknown set of organisms that might be non-culturable or obligate biotrophs. This study aims to characterize the actual fungal diversity present in Saharan dust using molecular and morphological identification tools. Standard DNA extraction methods, including commercial kits, do not work well due to the high concentration of salts and minerals in the soil and the resistance of the fungal material present in the sample. Therefore, to more accurately assess fungal diversity using environmental PCR techniques, more effective methods to extract DNA from filters and soil had to be tested. Dust samples were collected on transatlantic voyages during dust storm events through the Trans-Atlantic Saharan Dust AERosol and Ocean Science Expedition (AEROSE) from 2004 to present. To test the DNA extraction methods, soil samples from 2004, 2006, 2007, and 2008 filters and soil were used. Several cell lyses and pretreatment methods were tested, including 3 chemical pretreatments (AlNH4(SO4)2, CaCO3, CaCl2) and 4 mechanical lyses methods: vortex, sonication, stirring with heat, and freezer mill pulverization. Two different mechanical lyses were the most effective methods to extract DNA from the samples: stirring with heat and freezer mill pulverization since they provide the flexibility of extracting DNA from both types of samples and it also provides high yields. The preliminary survey shows a high phylogenetic diversity of fungi using ITS and LSU nuclear ribosomal DNA sequences.
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1 - Univeristy of Maryland, Planst Sciences and Landscape Architecture, 2102 Plant Sciences building, University of Maryland, College Park, MD, 20742, USA
2 - Howard University, Chemistry Department, 525 College Street, NW, Howard University, Washington, DC, 20059, USA
3 - University of Maryland, Department of Plant Sciences and Landscape Architecture, 2112 Plant Sciences Building, University of Maryland, College Park, MD, 20742, USA
direct DNA extraction
Presentation Type: Poster:Posters for BSA Sections
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM