Impact of DNA Extraction Strategies on Genomic and Bioinformatic Outcomes in Eight Selected Fungal Strains

Abstract

High-quality genomic DNA extraction remains a major bottleneck for fungal genomics, particularly for worldwide aerobic and non-photosynthetic mushroom species that rely on their rigid cell walls, interference between metabolites, polysaccharides, etc., and complex genomes. This study systematically compares five DNA extraction protocols involving four distinct sample preparation procedures (fresh (A), filtered (B), frozen (C) and cryogenic mycelium (D)) across mycelial cultures of eight Tunisian fungal strains representing Ascomycota and Basidiomycota to identify the optimal combination for genomic DNA extraction from mycelium. The eight phylogenetically diverse fungal species were analyzed using short-read (MiSeq and NextSeq550) and/or long-read (MinION Mk1C) sequencing technologies, giving a depth coverage between 3.7× and 83×. The generation and quality of the assemblies were assessed within the Galaxy platform, which revealed a gap percentage of 0–0.509%. Taxonomic characterization and phylogenetic inference were performed with SANGER technology using the Internal Transcribed Spacer (ITS) and D1/D2 region of the 26S rRNA gene, assigning the species to our eight different strains: Clitopilus baronii (BS6), Porostereum spadiceum (BS200), Trametes versicolor (BS22-9), Schizophyllum commune (BS23-13), Gloeophyllum abietinum (BS23-14), Irpex laceratus (BS100), Trichoderma asperellum (GC9) and Trichoderma harzianum (S3). The optimized DNeasy Plant Pro Kit protocol with cryogenic biomass treatment presents a safe and cost-effective method for fungal genome sequencing and taxonomic resolution. This integrated comparative evaluation of extraction for sequencing identifies an optimal Qiagen-based extraction strategy combined with cryogenic treatment for eight diverse Tunisian fungal species, guiding method selection based on specific cell wall characteristics rather than proposing a universal protocol limited by unequal replication and strain numbers.