Chromosome-Level Genome Assembly of Morchella sextelata Reveals Its Early Divergence and Adaptive Evolution

This study presents a high-quality chromosome-level genome assembly of Morchella sextelata (54.64 Mb, 26 pseudochromosomes) and systematically characterizes its genomic and evolutionary features. Phylogenetic analysis indicates that M. sextelata diverged early within the Morchella genus (~14.2 million years ago) and underwent substantial genomic remodeling, with 1124 expanded and 1961 contracted gene families. Enrichment analysis of rapidly expanded gene families highlights two prominent functional themes: genes associated with small molecule/ion binding and secondary metabolite biosynthesis, and genes linked to the Fanconi anemia pathway and DNA repair/recombination. Notably, 56.96% of the COG-annotated M. sextelata-specific genes encode retrotransposon-related proteins, and this enrichment coincides with the expansion of DNA repair systems—a pattern reminiscent of the “transposon domestication” model. Functional genomic analyses further reveal that the glycoside hydrolase system is dominated by GH5, GH43, and GH3 families, suggesting a predicted capacity for plant cell wall polysaccharide degradation, while 12 biosynthetic gene clusters indicate genetic potential for terpenoid and non-ribosomal peptide biosynthesis. These findings provide a valuable genomic resource for M. sextelata and offer new insights into the role of transposable element mediated remodeling in fungal genome evolution.