Comparative Genomics of Fungi in Nectriaceae Reveals Their Environmental Adaptation and Conservation Strategies

This study presents the first genome assembly of the freshwater saprobe fungus <i>Neonectria lugdunensis</i> and a comprehensive phylogenomics analysis of the <i>Nectriaceae</i> family, examining genomic traits according to fungal lifestyles. The <i>Nectriaceae</i> family, one of the largest in Hypocreales, includes fungi with significant ecological roles and economic importance as plant pathogens, endophytes, and saprobes. The phylogenomics analysis identified 2684 single-copy orthologs, providing a robust evolutionary framework for the <i>Nectriaceae</i> family. We analyzed the genomic characteristics of 17 <i>Nectriaceae</i> genomes, focusing on their carbohydrate-active enzymes (CAZymes), biosynthetic gene clusters (BGCs), and adaptations to environmental temperatures. Our results highlight the adaptation mechanisms of <i>N. lugdunensis</i>, emphasizing its capabilities for plant litter degradation and enzyme activity in varying temperatures. The comparative genomics of different <i>Nectriaceae</i> lifestyles revealed significant differences in genome size, gene content, repetitive elements, and secondary metabolite production. Endophytes exhibited larger genomes, more effector proteins, and BGCs, while plant pathogens had higher thermo-adapted protein counts, suggesting greater resilience to global warming. In contrast, the freshwater saprobe shows less adaptation to warmer temperatures and is important for conservation goals. This study underscores the importance of understanding fungal genomic adaptations to predict ecosystem impacts and conservation targets in the face of climate change.