Genome Sequencing of Paecilomyces Penicillatus Provides Insights into Its Phylogenetic Placement and Mycoparasitism Mechanisms on Morel Mushrooms

Abstract

Morels (<i>Morchella</i> spp.) are popular edible fungi with significant economic and scientific value. However, white mold disease, caused by <i>Paecilomyces penicillatus</i>, can reduce morel yield by up to 80% in the main cultivation area in China. <i>Paecilomyces</i> is a polyphyletic genus and the exact phylogenetic placement of <i>P. penicillatus</i> is currently still unclear. Here, we obtained the first high-quality genome sequence of <i>P. penicillatus</i> generated through the single-molecule real-time (SMRT) sequencing platform. The assembled draft genome of <i>P. penicillatus</i> was 40.2 Mb, had an N50 value of 2.6 Mb and encoded 9454 genes. Phylogenetic analysis of single-copy orthologous genes revealed that <i>P. penicillatus</i> is in Hypocreales and closely related to Hypocreaceae, which includes several genera exhibiting a mycoparasitic lifestyle. CAZymes analysis demonstrated that <i>P. penicillatus</i> encodes a large number of fungal cell wall degradation enzymes. We identified many gene clusters involved in the production of secondary metabolites known to exhibit antifungal, antibacterial, or insecticidal activities. We further demonstrated through dual culture assays that <i>P. penicillatus</i> secretes certain soluble compounds that are inhibitory to the mycelial growth of <i>Morchella sextelata</i>. This study provides insights into the correct phylogenetic placement of <i>P. penicillatus</i> and the molecular mechanisms that underlie <i>P. penicillatus</i> pathogenesis.