Genomic insights into Fusarium oxysporum f. sp. cyclaminis: endorsing the causal agent of Fusarium wilt on cyclamen in Brazil

In 2023, a severe outbreak led to a 70% mortality rate among Cyclamen persicum plants in Holambra, S & atilde;o Paulo, prompting an investigation to identify the causal agent. Symptomatic plants were sampled, and the fungus, designated CMAA 1919, was isolated and identified through morphological analysis. Pathogenicity was verified via Koch's postulates, with inoculated plants replicating wilt symptoms. To support genomic characterization of the pathogen, whole-genome sequencing was conducted using the Illumina platform. Genomic DNA was extracted, sequenced, and processed, resulting in a 48.9 Mb genome with 200x coverage and 97.5% completeness. Phylogenetic analysis positioned CMAA 1919 within a Fusarium cluster, confirming its closest relation to Fusarium oxysporum strain Fo47 (99.07% genomic similarity) and other pathogenic strains. This study presents the first genomic and morphological description of Fusarium oxysporum f. sp. cyclaminis (CMAA 1919), the causative agent of Fusarium wilt in cyclamen in Brazil. This work presents the first sequencing of a representative isolate of Fusarium oxysporum f. sp. cyclaminis (Focy), one of the most damaging pathogens for cyclamen (Cyclamen persicum L.). The availability of the complete genome of Focy enhances our understanding of its biology, ecology, and pathogenicity, thereby facilitating the development of sustainable strategies for disease management and crop protection. Despite the previously reported occurrence of this pathogen based only on symptoms and pathogenicity tests on 1970s, the sequenced strain CMAA 1919 provides the first genomic and morphological description of this pathogen, which causes the Fusarium wilt on cyclamen in Brazil. This information provides a valuable safeguard for cyclamen cultivation, ensuring the long-term sustainability of this crop in the Brazilian ornamental plant market.