Poster Session: Population Genetics-Fungi

506-P

High-depth genome coverage of an unusual Gibberella fujikuroi species complex isolate that is cross-fertile with multiple species.
C. TOOMAJIAN (1), M. Chiara (2), W. Strouts (1), D. Horner (2), A. Logrieco (3), G. Pesole (4), J. F. Leslie (1), J. Stack (1)
(1) Kansas State University, Manhattan, KS, U.S.A.; (2) Università Degli Studi di Milano, Milano, Italy; (3) Istituto di Scienze delle Produzioni Alimentari, Consiglio Nazionale delle Ricerche, Bari, Italy; (4) Università Degli Studi di Bari, Bari, Italy

The study of natural plant pathogenic fungal isolates that are genetically intermediate between species may shed light on the frequency of interspecific hybridization and gene exchange in nature. Our goal was to perform an in-depth study of the genetic composition of such a potential natural hybrid between Fusarium fujikuroi (Ff) and F. proliferatum (Fp) collected from native prairie grass to test whether the isolate likely represents an interspecific hybridization event. Two genomic DNA libraries were sequenced with HiSeq 2000 for both the prairie sample and a representative Ff sample, and de novo assemblies were performed with the software Velvet. Megablast was used to identify likely homologous regions between these two samples and the published F. verticillioides (Fv) genome. Sequencing produced excellent depth of coverage for each sample, and de novo assembly and contig scaffolding resulted in N50s of 1 Mb and 180 kb for the prairie isolate and Ff sample, respectively. Scaffolds from each isolate were blasted against the Fv genome, and scaffolds from each of our sequenced strains blasting to the same Fv region were aligned. We used the extent and percent difference of well-aligned sequence to estimate divergence and investigated the distribution of divergences for evidence the prairie strain is a mosaic of Ff and Fp sequence. Our results have implications for the exchange of genes between related pathogen species on secondary hosts.