Verticillium alfalfae and V. dahliae, Agents of Verticillium Wilt Diseases

Verticillium dahliae and V. alfalfae (formerly Verticillium albo-atrum) are two important agricultural pathogens that affect many crops around the world and cause a distinct type of vascular wilt, which are known as Verticillium wilts. Several V. alfalfae and V. dahliae genomes have been sequenced, and are among the smaller genomes from filamentous ascomycetes. The number of predicted protein-encoding genes is similar to the saprobe Neurospora crassa. Perhaps reflective of their particular hemibiotrophic life styles, some gene families are expanded in the V. alfalfae and V. dahliae genomes. These include the gene families encoding glycoside hydrolases GH88, necrosis and ethylene-inducing-like proteins (NLPs), LysM effectors, proteins with chitin-recognition motifs, and cutinases. But the number of predicted secreted proteins was less than half that of the related Colletotrichum species, the agents of anthracnose diseases. V. dahliae strains generally contain lineage-specific regions (LS regions), which may play an important role in virulence and pathogenicity. Examples for horizontal transfer into Verticillium ancestors include the virulence factor Ave1, a glucan glucosyltransferase, and potentially some of the retrotransposons. The V. alfalfae and V. dahliae genomes have already had significant impacts on various aspects of basic and applied Verticillium research.