Diverse Upregulated Transcripts During Conidiation of the Aphid-Obligate Fungal Pathogen Conidiobolus Obscurus (Entomophthoromycotina)

Abstract

Filamentous fungi in the order Entomophthorales are the main natural regulators of insect populations. Conidiation is crucial for entomopathogenic fungi to explore host resources due to the multifunction of conidia such as growth, infection, and stress resistance; however, the molecular mechanisms underlying the conidial functions in Entomophthorales is unknown. This study analyzed the differentially expressed transcriptomic patterns in three conidiation stages (pre-conidiation, emerging conidiation, and post-conidiation, respectively) of the aphid-obligate pathogen Conidiobolus obscurus (Entomophthoromycotina). The emerging conidiation stage vs. pre- or post- conidiation stage had 3,091 and 3,235 differentially expressed genes (DEGs), respectively, wherein 2,915 upregulated DEGs were putatively related to the conidial functions. A weighted gene co-expression network analysis showed that 772 hub genes in conidiation, which were related to cuticular component degradation, oxidative phosphorylation, ribosomal biogenesis, cell wall/membrane biosynthesis, MAPK signaling pathway, secondary metabolite biosynthesis, and other metabolic processes. This implied that the conidia of Entomophthorales have abundant transcripts with various functions to favor a quick response to the surrounding environment and effectively explore the host resources.