The Genome of Pseudocercospora cladosporioides: A Step Toward Understanding Olive Cercosporiosis

Abstract

Pseudocercospora cladosporioides is the causal agent of Cercospora leaf spot, a defoliating disease of olive trees, particularly in the Mediterranean Basin. Despite its agricultural relevance, genomic resources for this pathogen remain scarce, partly due to difficulties in isolating the fungus outside its host and obtaining high-­quality DNA. Here, we report the assembly and annotation of the first high-quality genome of P. cladosporioides, providing valuable genomic insights for future studies on olive-pathogen interactions. Using Oxford Nanopore Technologies for long-­read sequencing and Illumina for short-­read sequencing, we obtained an initial genome assembly totalling 53,422,737 bp, comprising 248 scaffolds with an N50 of 509 kb, and a BUSCO gene completeness of 98.9%. Gene prediction analysis identified 14,429 protein-­coding genes, of which 491 genes are predicted to encode carbohydrate-­active enzymes. Additionally, 27 gene clusters involved in secondary metabolite biosynthesis were identified. A total of 434 proteins were predicted as effectors using an in silico pipeline. This genomic resource represents a critical step toward understanding the molecular mechanisms underlying P. cladosporioides infections and contributes to developing effective disease management strategies for olive crops.