Genome-wide study of saprotrophy-related genes in the basal fungus Conidiobolus heterosporus

Myochromella unveiled: exploring its global distribution through a public database of amplicons

Myochromella mammosa, a novel species from southwestern China, is distinguished by its small, solitary or gregarious basidiomata. The pileus is clock-shaped, with distinct central mastoids, edge stripes, and a darker center that flattens upon maturation. The stipe is white, firm when young, and becomes hollow and slightly thickened at the base with age. We conducted a comprehensive analysis of publicly available ITS sequences from NCBI-GenBank and fungal amplicon sequencing data from NCBI-SRA to explore the global distribution and enumeration of recorded species of Myochromella. At a 98% sequence similarity threshold, eleven species were identified, including eight without formal designations. Myochromella's diversity is primarily Northern Hemisphere-centric and tends toward endemic distribution. Leveraging amplicon sequencing data sets enables precise species diversity assessments, enhancing field collection efficiency and providing novel insights into macrofungal species diversity.

Genome-Wide Study of Conidiation-Related Genes in the Aphid-Obligate Fungal Pathogen Conidiobolus obscurus (Entomophthoromycotina)

Fungi in the Entomophthorales order can cause insect disease and epizootics in nature, contributing to biological pest control in agriculture and forestry. Most Entomophthorales have narrow host ranges, limited to the arthropod family level; however, rare genomic information about host-specific fungi has been reported. Conidiation is crucial for entomopathogenic fungi to explore insect resources owing to the important roles of conidia in the infection cycle, such as dispersal, adhesion, germination, and penetration into the host hemocoel. In this study, we analyzed the whole genome sequence of the aphid-obligate pathogen Conidiobolus obscurus strain ARSEF 7217 (Entomophthoromycotina), using Nanopore technology from Biomarker Technologies (Beijing, China). The genome size was 37.6 Mb, and encoded 10,262 predicted genes, wherein 21.3% genes were putatively associated to the pathogen–host interaction. In particular, the serine protease repertoire in C. obscurus exhibited expansions in the trypsin and subtilisin classes, which play vital roles in the fungus’ pathogenicity. Differentially expressed transcriptomic patterns were analyzed in three conidiation stages (pre-conidiation, emerging conidiation, and post-conidiation), and 2915 differentially expressed genes were found to be associated with the conidiation process. Furthermore, a weighted gene co-expression network analysis showed that 772 hub genes in conidiation are mainly involved in insect cuticular component degradation, cell wall/membrane biosynthesis, MAPK signaling pathway, and transcription regulation. Our findings of the genomic and transcriptomic features of C. obscurus help reveal the molecular mechanism of the Entomophthorales pathogenicity, which will contribute to improving fungal applications in pest control.