Characterization of transcriptomic changes across Coccidioides morphologies using RiboMarker®-enhanced RNA sequencing

Area of Science:

• Mycology
• Molecular Biology
• Pathogenomics

Background:

• Coccidioides fungi cause Valley fever, a significant mammalian disease.
• Previous research focused on transcriptomes, neglecting small RNA roles in Coccidioides pathogenesis.
• Small RNAs are critical in fungal host-pathogen interactions, influencing virulence.

Purpose of the Study:

• To analyze small RNA expression across Coccidioides posadasii morphologies (arthroconidia, mycelia, spherules).
• To investigate intracellular and extracellular small RNA profiles during life stage transitions.
• To identify novel genes and loci involved in Coccidioides saprobic and parasitic cycles.

Main Methods:

• Utilized RiboMarker® for small RNA and RNA fragment library preparation.
• Analyzed small RNA expression across arthroconidia, mycelia, and spherule morphologies.
• Examined both intracellular and extracellular RNA fractions.

Main Results:

• Observed transcriptomic shifts involving protein-coding, tRNA, and unannotated loci during morphological transitions.
• Identified unique RNA fragmentation patterns correlating with Coccidioides ecotypes.
• Detected extracellular export of snRNA, tRNA-derived fragments, and mRNA transcripts.

Conclusions:

• Small RNA profiles provide crucial insights into Coccidioides life stage transitions.
• RNA fragmentation patterns may serve as ecotype-specific markers.
• Extracellular RNA export suggests roles in cell-cell and host-pathogen communication, potentially aiding biomarker discovery for Valley fever.