First report and draft genome resource of a unique opportunistic Fusarium solani pathogen associated with unknown dark galls in sugarbeet

Abstract

Fusarium disease of sugarbeet is a threat to sugarbeet production and can cause significant losses. During routine evaluation, a unique Fusarium species was solely isolated from unknown dark galls in sugarbeets from Wilkin County, MN, USA. Analysis of the RPB2 gene placed this isolate in the Fusarium solani FSSC 5 clade (100.0% similarity) but uniquely separated from the potato F. solani. Sequencing of this Fusarium species by Minion Nanopore Systems resulted in a draft genome assembly of 19 contigs with a genome size of 59.3 Mb and GC content of 50.66%. A total of 18,900 protein-coding genes, 37 secondary metabolite clusters, 1,559 secreted proteins, 668 carbohydrate-active enzymes, and 404 effectors were predicted in the genome. Pathogenicity tests showed mild vascular discoloration in inoculated sugarbeets unaccompanied by external symptoms suggesting weak pathogenic ability of this species, indicative of an opportunistic pathogen. These results extend our understanding of this unique opportunistic Fusarium solani isolated from sugarbeet.