Characterization of Mitogenomes from Four Mucorales Species and Insights into Pathogenicity.

Background Mucorales, as one major order of Zygomycetes fungi, can infect human beings and cause serious consequence. We have noticed the pathogenicity of Mucorales is closely related to energy metabolism, while mitochondria play the role of energy factories in almost all biological activities. Methods Virulence of M. irregularis, M. hiemalis, L. corymbifera and R. arrhizus were verified in Galleria mellonella larvae, as well as mitochondrial gene copies analyzed with RT-qPCR. Mitogenomes of the four Mucorales species were sequenced based on illumina NovaSeq technology to study their characteristic features and functional regions. Results Variant virulence of M. irregularis, M. hiemalis, L. corymbifera and R. arrhizu were verified by clinical retrospective data and our G. mellonella infection models, also copies of mitochondrial genes indicated the significant associations with pathogenicity. A total of 274.18 clean reads were generated to be assembled, the complete mitogenomes of the four Mucorales species were obtained with totally different length. After the genomes annotated and compared, M. irregularis was found more similar with M. hiemalis than those of L. corymbifera and R. arrhizus, especially the small (rrns) and large (rrnl) subunits of mitochondrial ribosomal RNA (rRNA) genes. The GC content, ncRNAs and the distribution of the SNPs and InDels were also compared, and the GC content rate of fungi seems to be related to the fungal thermal adaptability. In addition, linear mitogenomes of these four Mucorales showed diverse arrangements of orf genes and directionality of some conserved gene elements. Conclusion This study uncovered the pathogenicity variances among the four Mucorales species and the relationship between their mitogenomic features and clinical pathogenicity. Further studies like spatial structure of mitochondrial genomes and the comprehensive analysis of transcription regulation are needed.