The Telomere-to-Telomere Genome and Lifestyle Transcriptome Profiling of Discula destructiva , the Causal Agent of Dogwood Anthracnose

Fungal pathogens have dramatically altered forests worldwide, yet the mechanisms of virulence remain poorly understood. From the 1970s to the early 2000s, dogwood anthracnose, caused by Discula destructiva, devastated North American flowering and Pacific dogwoods ( Cornus florida and C. nuttallii, respectively), causing one of the most destructive forest tree epidemics of the modern era. Despite its ecological impacts, genomic resources for D. destructiva and related Diaporthales pathogens remain limited, thus hindering efforts to resolve the mechanisms of pathogenicity. Here, we present the telomere-to-telomere genome assembly of D. destructiva, complemented by transcriptome profiling to investigate gene expression shifts across its hemibiotrophic life cycle. The 46.655-Mb assembly comprised eight chromosomes with 99.47% BUSCO completeness, along with 10,373 predicted gene models with 97.40% BUSCO completeness. To profile life cycle-specific gene expression, we conducted RNA sequencing of sporulating (reproductive) and nonsporulating (vegetative) tissue and identified 240 differentially expressed genes ( Padj < 0.05). Of those, 162 upregulated sporulation genes were associated with plant cell wall degradation and sugar metabolism, whereas 78 downregulated sporulation genes were associated with oxidative stress response and metal ion homeostasis. Of the 240 sporulation genes, 117 genes also encoded predicted virulence factors, including signal peptides, carbohydrate-active enzymes (CAZymes), and effectors. These patterns suggest a metabolic reallocation accompanying the transition to sporulation, which reflects physiological adaptation in response to environmental factors. Together, these findings illuminate the hemibiotrophic adaptation of D. destructiva and provide high-quality genomic tools for future comparative and functional studies. [Formula: see text]