Comparative genomics of the plant vascular wilt pathogens, Verticillium dahliae and Verticillium albo-atrum

Verticillium dahliae and Verticillium albo-atrum are plant pathogenic fungi that cause Verticillium wilts worldwide. The 7.5 X sequence of V. dahliae strain VdLs.17 and the 4 X sequence of V. albo-atrum strain VaMs.102 were generated and assembled at the Broad Institute using Sanger sequencing. A comparison of these genomes revealed a high level of synteny between these two Verticillium species, and led to the identification of a set of potential effector proteins. In particular, our study revealed higher numbers of pectinolytic enzymes in the Verticillium species than in other fungi, which may have direct implications in the ability of these pathogens to colonize a wide range of plant hosts. Additionally, we identified in the genome assembly of V. dahliae strain VdLs.17 four lineage-specific (LS) regions which are absent from VaMs.102. Certain gene families in the transposon-rich LS regions have undergone expansion, including transcription factors, ferric reductases, and phospholipases, which collectively may facilitate niche adaptation. Comparative analyses with another vascular wilt fungus, Fusarium oxysporum, revealed a conserved set of proteins that may have particular relevance for these vascular wilt fungi. These findings provide insight into the molecular determinants that underpin pathogenicity and niche adaptation in these vascular wilt fungi, and provide a foundation for functional genomics analyses.