Functional characterization of the RNA interference pathway in A. fumigatus reveals its potential for antifungal therapy

ABSTRACT: The RNA interference (RNAi) pathway has evolved numerous functionalities in eukaryotes, with many on display in Kingdom Fungi. RNAi can regulate gene expression, facilitate drug resistance, or even be altogether lost to improve growth potential in some fungal pathogens. In the WHO fungal priority pathogen, Aspergillus fumigatus, the RNAi system is known to be intact and functional. To extend our limited understanding of A. fumigatus RNAi, we first investigated the genetic variation in RNAi-associated genes in a large collection of environmental and clinical genomes, where we found that RNAi is evolutionarily conserved even in clinical strains. Using endogenously expressed inverted-repeat transgenes complementary to both a conditionally essential gene and a nonessential gene, we determined that a subset of the RNAi componentry is active in inverted-repeat transgene silencing in conidia and mycelium. A multi-condition mRNA-seq analysis linked the A. fumigatus dicer-like enzymes and RNA-dependent RNA polymerases to regulation of conidial ribosome biogenesis genes; however, surprisingly few endogenous small RNAs were identified in conidia that could explain this broad change. Although RNAi was not clearly linked to growth or stress response defects in the RNAi knockouts, serial passaging of RNAi knockout strains for six generations resulted in lineages with diminished spore production over time, indicating that loss of RNAi can exert a fitness cost on the fungus. Cumulatively, A. fumigatus RNAi appears to play an active role in defense against double-stranded RNA species alongside a previously unappreciated housekeeping function in regulation of conidial ribosomal biogenesis genes.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Neosartorya Fumigata (aspergillus Fumigatus)

SUBMITTER: Thomas Krüger  

LAB HEAD: Axel A. Brakhage

PROVIDER: PXD039739 | Pride | 2023-02-17

REPOSITORIES: Pride