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Comparative genomic analysis of Fusarium oxysporum f. sp. vasinfectum isolates and their small secreted proteins

Seungyeon Seo: Auburn University

<div><em>Fusarium oxysporum</em> f. sp. <em>vasinfectum</em> (Fov) causing vascular wilt disease is one of the most devastating pathogens of cotton (<em>Gossypium</em> spp). To elucidate the molecular mechanisms responsible for host-specificity for pathogenicity on cotton, five Fov isolates were sequenced using PacBio SMRT sequencing and the genomes compared with 10 <span><em>F. oxysporum</em></span> genomes that are non-virulent on cotton. Genome analysis revealed that the highly virulent genotype race 4 had the largest genome size and coding genes and repetitive elements, compared to the other four Fov isolates. The genome of <em>F. oxysporum</em> comprises both core and accessory regions, and all the genomes of the Fov isolates were able to be divided into these two main architectures based on the genome of <em>F. oxysporum</em> f. sp. <em>lycopersici</em> (Fol) as a reference. Comparative analysis among both cotton and non-cotton isolates of <em>F. oxysporum</em> focused on small secreted proteins (SSPs), which may function as virulence factors termed fungal effectors. The results showed that all isolates had similar proportions of SSPs based on the whole genome following a universal effector prediction pipeline. A total of 165 proteins were common to all the different <em>formae speciales </em>of <em>F. oxysporum. </em>Importantly, 56 SSPs are unique to the most virulent genotype and 17 SSPs existed only in the cotton Fov isolates. In summary, each Fov isolate genome reflects the diversity of pathogenesis-related genomic features, sharing or differing from each other, and may yield insights into the development of disease management strategies for cotton wilt.</div>