Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 2, 2007
Publication Date: September 4, 2007
Citation: Rossman, A.Y. 2007. Progress toward DNA barcoding the vast diversity of fungi. Meeting Abstract.
The Fungi are a group of organisms essential for life on Earth. Although 1.5 million species may exist, only about 120,000 species have described and characterized. With 90-99% of the fungi still unknown, it is expected that a great deal of diversity would be revealed through DNA barcoding as demonstrated by studies using environmental sampling in which major new lineages have been revealed. The issue of developing DNA barcodes for Fungi was addressed at an international workshop held in May, 2007. The goals of the meeting were to arrive at a consensus on a standard gene region for barcoding fungi and to brainstorm and prioritize projects. Experiences with use of the CO1 gene as a barcode have produced mixed results. Although the CO1 gene works for the non-fungal group Oomycota and a few groups of true Fungi, there are problems in using this gene as a DNA barcode for most true Fungi. These problems involve amplification because of extreme length variation in the mitochondrial genomes that result from the unpredictable presence of multiple and sometimes mobile introns of differing lengths. The consensus of the participants at the workshop was that the most appropriate gene known at present for DNA barcoding of true Fungi is the entire ITS region of the nuclear rDNA. Fungal-specific ITS primers exist, have been widely applied, and are known to work well across the major groups of fungi. On the other hand, in some groups of fungi, the ITS region is too variable to determine major group such as for yeast fungi and members of the Glomeromycota. For other groups, the ITS region does not distinguish individual species especially from plant pathogenic ascomycetes. Ideas about potential DNA barcoding projects of fungi involved fungi in the air, for example, for ecologists tracking the distribution of fungi from habitats such as the Saharan desert, plant quarantine officials tracking the movement of invasive fungi and plant pathogens, and physicians checking the distribution of fungi that cause allergies; fungi associated with global trade that threaten biosecurity for which rapid identification techniques are needed to prevent the spread of invasive species; fungi of boreal forests impacted by global climate change; and medically important fungi that are increasing in number and variety for immunocompromised humans. Those most excited about the application of this technology are ecologists working with environmental samples working to determine the role of fungi in, for example, belowground systems associated with roots of forest trees. In addition, DNA barcoding of fungi would be extremely useful to biosecurity and agricultural quarantine agencies around the world to prevent the spread of invasive fungi.