Fusarium musae, a pathogen crossing “borders”

Fusarium musae is an agent of crown rot in banana fruits and was recently isolated as cause of keratitis and nail infection as well as cause of systemic infections in immunocompromised patients. It is a sister species to F. verticillioides. To confirm the hypothesis that F. musae is a cross kingdom pathogen, strains of F. musae (n=19), isolated worldwide from banana fruits and human patients were characterised in comparative analyses. Plant and human strains did not group according to their host origin by morphological, nuclear and mitochondrial molecular analyses. In vitro sensitivity to azoles widely used in agricultural and clinical settings showed that F. musae is less sensitive than its “sister species” F. verticillioides. No significant differences were observed between human and banana strains. In vivo infection on banana fruits and Galleria mellonella (as “human proxy”) demonstrated that both, banana and human strains, are able to invade both pathosystems causing comparable levels of infection. Complete genomes of 2 representative strains were assembled on chromosomal level, and these strains were used to generate fluorescent and luminescent F. musae reporter strains that will be used to study the interaction with both hosts. A survey from bananas sold on local market confirmed that F. musae can be isolated from fruit shipped from different producing countries. Our work proved that F. musae is a cross-kingdom pathogen likely originating in agricultural settings.