Karst habitats are hotspots of diversity and endemism. Their naturally fragmented distributions across broad geographic landscapes have led to a complex array of smaller evolutionary ecosystems. Comprehensive biodiversity assessments of karst habitats have revealed that these ecosystems contain a high level of endemism. During a survey of cordycipitoid fungi in the karst region of southwest Guizhou, China, we identified and proposed two new species, based on morphology and multi-locus (nrSSU, nrLSU, tef, rpb1, and rpb2) phylogenetic analyses. O. cystidiatasp. nov. is characterized by gray-white to yellow fertile part, verrucose phialides, and conidia enveloped in a cystic thickened mucus sheath, distinguishing it from other species. O. sinocampessp. nov. is distinguished by long tapering phialides with inflated bases. Phylogenetic analyses using five loci reveal that O. cystidiata shares a close relationship with O. fenggangensis, O. musicaudata, O. alboperitheciata, and Hirsutella kuankuoshuiensis, while O. sinocampes is closely related to O. multiperitheciata and H. strigosa. Herein, we completed the descriptions, illustrations and molecular phylogeny of these two new species. The host diversity of O. sinocampes has also been documented within the orders Lepidoptera and Coccoidea. Our research further enriches the diversity of cordycipitoid species in the typical karst landform areas of Guizhou, China.

In recent years, the herpes virus infectious hypothesis for Alzheimer’s disease (AD) has gained support from an increasing number of researchers. Herpes simplex virus (HSV) is a potential risk factor associated with AD. This study assessed whether HSV has a causal relationship with AD using a two-sample Mendelian randomization analysis model. Six single-nucleotide polymorphisms (SNPs) associated with HSV-1 and thirteen SNPs associated with HSV-2 were used as instrumental variables in the MR analysis. We estimated MR values of relevance between exposure and the risk of AD using inverse-variance weighted (IVW) method, MR-Egger regression (Egger), and weighted median estimator (WME). To make the conclusion more robust and reliable, sensitivity analyses and RadialMR were performed to evaluate the pleiotropy and heterogeneity. We found that anti-HSV-1 IgG measurements were not associated with risk of AD (OR, 0.96; 95% CI, 0.79–1.18; p = 0.736), and the same was true for HSV-2 (OR, 1.03; 95% CI, 0.94–1.12; p = 0.533). The findings indicated that any HSV infection does not appear to be a genetically valid target of intervention in AD.

Ophiocordyceps is an entomopathogenic fungal genus with global distribution and considerable economic implications in both biological control and biomedicine. However, the species diversity of Ophiocordyceps remains to be further investigated. In this study, a new species, Ophiocordyceps xifengensis, found parasitizing lepidopteran pupae, was discovered during a survey of insect pathogenic fungi in Xifeng County, Liaoning Province. Morphological comparative analysis revealed that this species characterized by having solitary, non-branching, woody, cylindrical asci and filamentous ascospores. Compared to its closely related species, the new species exhibits inclined embedded perithecia (0.38–0.43 mm) and smaller asci (164.8–178.9 × 7.4–10.2 μm), with its anamorphic features. Phylogenetic analysis based on multiple gene sequence data infers that Ophiocordyceps xifengensis, forming a distinct branch from other closely related species.

Ophiocordyceps holds significant importance in forest arthropod population regulation, biological control of agricultural pests, and the development of bioactive substances. Investigating the microbial community composition of wild Ophiocordyceps is significant for understanding its individual development process, understory cultivation, and taxonomy. In this study, a novel insect pathogenic fungus, Ophiocordyceps zhenxingensis , parasitizing Hymenoptera larvae, originating from Liaoning Province, China, was delineated based on morphology and phylogenetics. The microbial communities in the sclerotium and host surface complex of its different reproductive stages (sexual and asexual) were investigated. O. zhenxingensis was detected within the Hirsutella citriformis subclade, being closely related to Hirsutella gigantea and Ophiocordyceps elongata . It was morphologically characterized by solitary or multiple stromata, semi-submerged perithecia, and viscous basidiospores. Proteobacteria, Actinobacteriota, and Bacteroidota were the major bacterial taxa, and Basidiomycota and Ascomycota were the major fungal taxa. Tomentella , Sebacina , and Russula were abundant in the host surface complex that belongs to mycorrhizal fungi. The microbial co-occurrence network suggested that microbial relationships were predominantly positive correlations, and positive correlations were more pronounced in the asexual stage than the sexual stage. The microbial co-occurrence network of O. zhenxingensis was more complex during the asexual stage; it exhibited greater metabolic activity during the asexual stage. These results have enhanced our understanding of the composition, diversity, and functions of the endophytic microbial community of Ophiocordyceps , furnishing additional evidence for classifying its sexual and asexual stages and establishing a theoretical basis for subsequent research on its individual development. IMPORTANCE: Ophiocordyceps exhibits two distinct life stages (asexual and sexual) in its natural environment. The symbiotic microorganisms associated with the fungus play a crucial role in its growth and development. We have identified a new species, Ophiocordyceps zhenxingensis , which belongs to the Hirsutella citriformis subclade. A large number of mycorrhizal fungi were found in the insect appendages of O. zhenxingensis , whereas the fungal community within the sclerotium was predominantly composed of Ascomycota. During the asexual stage, O. zhenxingensis exhibited greater microbial diversity and stronger positive correlations among microorganisms. Additionally, it possesses a richer array of metabolic pathways. These results have deepened our knowledge of the composition, diversity, and roles of the microbial community in Ophiocordyceps , providing further evidence for distinguishing its sexual and asexual stages and laying a theoretical foundation for future research on its developmental processes.

Exopolysaccharide (EPS) synthesis of halophilic microorganisms is often reported as an adaptation to high-salt environments, and the unique structural and