Genetic diversity of Ophiocordyceps sinensis, a medicinal fungus endemic to the Tibetan Plateau: Implications for its evolution and conservation

Abstract

BackgroundOphiocordyceps sinensis (syn. Cordyceps sinensis), endemic to alpine regions on the Tibetan plateau, is one of the most valuable medicinal fungi in the world. Huge commercial demand has led to excessive harvest and a dramatic decline in its numbers. The diversity of terrains and climates on the Tibetan Plateau and the broad insect host range (more than 50 species in the family Hepialidae) may have resulted in substantial intraspecific genetic diversity for this fungus. The objective of this study was to evaluate the population distribution of O. sinensis from geographically diverse regions of the Tibetan Plateau based on nrDNA ITS and MAT1-2-1 gene sequences. Understanding of the genetic diversity and genesis of O. sinensis will provide important information for the evolution and conservation of this fungus.ResultsSignificant sequence variations in the ITS and MAT1-2-1 genes (27 and 23 informative sites, eight and seven haplotypes, respectively) were observed. Phylogenetic analysis based on ITS sequences, MAT1-2-1 sequences, or their combined data set, clustered isolates from northern regions in one clade (clade I), whereas isolates from southern regions were dispersed in all four clades (clade I-IV). Single-strand conformation polymorphism (SSCP) analyses of 2639 ITS clones from seven samples revealed 91 different SSCP patterns that were subsequently sequenced. ITS heterogeneity was found in XZ-LZ07-H1 (Nyingchi population), and 17 informative sites and five haplotypes were detected from 15 clones. The five haplotypes clustered into three clades (clade I, II, and IV).ConclusionsSignificant genetic divergence in O. sinensis was observed and the genetic diversification was greater among southern isolates than that among northern isolates. The polymorphism of nrDNA ITS sequences suggested that O. sinensis spread from a center of origin (the Nyingchi District) to southern regions and subsequently to northern areas. These results suggest that southern populations are important reservoirs of genetic diversity and should be taken into account in conservation programs.

Calcarisporium cordycipiticola sp. nov., an important fungal pathogen of Cordyceps militaris

“…Sung et al, is one of the most valuable medicinal fungi, and is endemic to the alpine regions on the Tibetan plateau. This species has yet to be cultivated and the huge commercial demand has led to excessive harvest and a dramatic decline in its number, and the price for natural O. sinensis has increased dramatically (Zhang 2009). Cordyceps militaris has similar chemical and medicinal properties as O. sinensis (Zheng et al 2011;Dong et al 2012;De Silva et al 2013) and is relatively easily cultured in both solid and liquid media and with a variety of carbon and nitrogen sources (Shrestha 2012).…”

Taxonomy and phylogeny of Puccinia lagenophorae: a study using rDNA sequence data, morphological and host range features

“…Highest genetic diversity is a feature typical for the place of origin of fungi (e.g. Zhang et al 2009). …”

Cordyceps militaris (Hypocreales: Cordycipitaceae): transcriptional analysis and molecular characterization of cox1 and group I intron with putative LAGLIDADG endonuclease

“…Although the cox1 genes from only four species of Cordycipitaceae fungi are present in the GenBank now, over 500 species of Cordycipitaceae fungi were described (Sung et al 2007). The molecular markers for the identification of Cordycipitaceae included the nuclear ribosomal small and large subunits, the elongation factor 1a, the largest and the second largest subunits of RNA polymerase II, b-tubulin, mitochondrial ATP6 and matingtype genes (Zhang et al 2009;Sung et al 2007), and mostly nuclear ribosomal DNA (Zhang et al 2009;Kuo et al 2005;Stensrud et al 2005;Chen et al 2004). Further description of cox1 genes of Cordycipitaceae fungi is required to enrich the database for molecular identification.…”