An overview on DNA barcoding: a new horizon in fungal molecular diagnostics

Total number of fungal species has been estimated over 1. 5 million، of which less than 10 percent have formally been described. Advances made in molecular biology، development of gene and genome sequence technologies، discovery and description of new species among different clusters of life، especially fungi، has been accelerated. With respect to the failure of morphological-based species recognition methods for fungi identification، use and application of DNA based identification methods have assumed great importance for rapid and accurate identification of fungal species. DNA barcoding is of central importance among the new approaches for the identification of fungi and pseudo fungi and has been used during the last 10 years. For fungi، the internal transcribed spacer region of ribosomal DNA (ITS-rDNA) has become an appropriate barcode. Efficacy of ITS-rDNA sequence data in successful identification of fungal species has resulted in general agreement among mycologists to use ITS-rDNA region as a gold standard barcode for fungi. However، it seems that ITS-rDNA region will be used as the primary barcode for identification of fungal species and accurate identification will further be performed by use of sequence data from the other genomic loci as secondary barcodes. Considering the pleomorphic nature of the fungi، use of DNA barcoding has assumed higher importance. Hundreds of thousands of reference barcodes have been generated for a great number of species by DNA barcoding projects. Scientists now are facing new challenges for barcode data management، facilitation and acceleration in species identification process using DNA barcodes by the end-users through automation of DNA barcoding system.