DNA barcoding the commercial Chinese caterpillar fungus

Abstract

Chinese caterpillar fungus (Ophiocordyceps sinensis) has been widely used as tonic in Asian medicine. Considering its curative effect and high cost, various counterfeit versions of O. sinensis have been introduced and are commercially available. These counterfeits have morphological characteristics that are difficult to distinguish based on morphology alone, thereby causing confusion and threatening its safe use. In this study, internal transcribed spacer (ITS) sequences as a DNA barcode were analyzed and assessed for rapid and accurate identification of 131 O. sinensis samples and 12 common counterfeits and closely related species. Results showed that sufficient ITS sequence differences, also known as 'barcode gaps', existed to distinguish between O. sinensis and counterfeit species. ITS sequence correctly identified 100% of the samples at the species and genus level using the Basic Local Alignment Search Tool 1 and the nearest distance method. Furthermore, O. sinensis, counterfeits, and closely related species can be successfully identified using tree-based methods including maximum parsimony, neighbor-joining, and maximum likelihood analysis. These results indicated that DNA barcoding could be used as a fast and accurate identification method to distinguish O. sinensis from counterfeits and closely related species to ensure its safe use.

Internal transcribed spacer 2 barcode: a good tool for identifying Acanthopanacis cortex

“…DNA barcoding has been widely used to identify herbs in recent years. Xiang et al ( 2013 ) accurately identified 131 Ophiocordyceps sinensis (Berk.) G. H. Sung samples, as well as 12 common counterfeits and its closely related species by using DNA barcoding.…”

Cordyceps collected from Bhutan, an appropriate alternative of Cordyceps sinensis

“…1A). Therefore, Bhutanese Cordyceps was further identified using DNA barcoding method, which has been widely applied for species identification of animals, plants and fungi1718. Indeed, the nuclear ribosomal internal transcribed spacer (ITS) region has been considered as a universal DNA barcode marker for fungi identification19.…”

Detection of Ophiocordyceps sinensis and Its Common Adulterates Using Species-Specific Primers

“…Genomic DNA was extracted from the resulting powders using a Tiangen Plant DNA Kit (Tiangen Biotech, China). The ITS regions were amplified using an LA Taq polymerase chain reaction (PCR) kit (Takara Biotech Inc.) with the universal primer pairs 5F (5′-GGAAGTAAAAGTCGTAACAAGG-3′)/4R (5′-TCCTCCGCTTATTGATATGC-3′; Li et al, 2013). The PCR mixture contained 0.1 μL of LA Taq (5 U μL −1 ), 2.5 μL of 10 × LA Taq PCR buffer II (Mg 2+ Plus), 1 μL of dNTP mixture (2.5 mM each), 0.6 μL of each primer (10 μM), and 1 μL (~120 ng) of genomic DNA in a total volume of 25 μL.…”