Abstract
Objective To examine the differential occurrence of Ophiocordyceps sinensis genotypes in the stroma, stromal fertile portion (SFP), and ascospores of natural Cordyceps sinensis.
Methods Immature and mature C. sinensis were harvested. Mature C. sinensis were continuously cultivated in our laboratory (altitude 2,200 m). The SFPs (with ascocarps) and ascospores of C. sinensis were collected for microscopic and molecular analyses using species-/genotype-specific primers.
Results Fully and semi-ejected ascospores were collected from the same specimens. The semi-ejected ascospores tightly adhered to the surface of the asci. The multicellular heterokaryotic ascospores showed uneven staining of nuclei. The ascospores were found to contain several genotypes of O. sinensis, Samsoniella hepiali, and an AB067719-type fungus. The genotypes within AT-biased Cluster-A occurred in all compartments of C. sinensis, but those within AT-biased Cluster-B were absent in the ascospores. Genotypes #13‒14 of O. sinensis occurred differentially in fully and semi-ejected ascospores, which featured DNA segment substitutions and genetic material recombination between the genomes of the parental fungi, Hirsutella sinensis and the AB067719-type fungus. These offspring genotypes combined with varying abundances of S. hepiali in the 2 types of ascospores participated in the control of the development, maturation and ejection of the ascospores.
Conclusion Multiple genotypes of O. sinensis coexist differentially in the SFP and 2 types of C. sinensis ascospores, along with S. hepiali and the AB067719-type fungus. The fungal components in different combinations and their dynamic alterations in the compartments of C. sinensis during maturation play symbiotic roles in the lifecycle of natural C. sinensis.
Competing Interest Statement
The authors have declared no competing interest.
