Two GC‐biased genotypes of Ophiocordyceps sinensis with distinct maturational patterns in the stroma of Cordyceps sinensis

Abstract

We reported simultaneous detections of the rDNA of Paecilomyces hepiali and at least 5 Ophiocordyceps sinensis (Os) genotypes in Cordyceps sinensis (Cs), the precious Chinese herb for anti‐aging. Southern blotting following EcoRI digestion showed 2 groups of genotypes, EcoRI sensitive (GC‐biases) and EcoRI resistant (AT‐biases and other mutants). SNP genotyping revealed multiple mutants in Cs with transition or transversion point mutations, differentially expressed in Cs stroma and caterpillar. Cs maturation associates altered expressions and phenotypes of these fungal species or mutants. In this study, we found that GC‐biased genotypes expressed little in the premature Cs stroma, but predominantly in the premature caterpillar. The differential expression was altered non‐proportionally with Cs maturation. Two GC‐biases were identified having identical sequences: (1) Hirsutella sinensis and (2) a moiety truncated at its 5′ and 3′ ends. The 2 GC‐biases have distinct expression patterns during Cs maturation. In conclusion, Cs stroma contains 2 GC‐biased genotypes with distinct maturation patterns. It remains to be determined if the 2 GC‐biases and all other Os genotypes are intra‐ or inter‐species mutants. Although ITS sequencing has been widely used for fungal species identification, our data indicates that the method may have limited power in distinguishing between fungal mutants.