January 15-19, 2011
Town & Country Convention Center
San Diego, CA
Steven J. Klosterman1 , Krishna V. Subbarao2 , Seogchan Kang3 , Paola Veronese4 , Scott E. Gold5 , Bart P. H. J. Thomma6 , Zehua Chen7 , Bernard Henrissat8 , Yong-Hwan Lee9 , Jongsun Park9 , Maria D. Garcia-Pedrajas10 , Dez J. Barbara11 , Amy Anchieta1 , Ronnie de Jonge6 , Parthasarathy Santhanam6 , Karunakaran Maruthachalam2 , Zahi Atallah2 , Stefan G. Amyotte12 , Zahi Paz5 , Patrik Inderbitzin2 , Ryan J. Hayes1 , David I. Heiman7 , Sarah Young7 , Qiandong Zeng7 , Reinhard Engels7 , James Galagan7 , Christina Cuomo7 , Katherine F. Dobinson12 , Li-Jun Ma7
The vascular wilt fungi Verticillium dahliae and V. albo-atrum infect over 200 plant species, causing billions of dollars in annual crop losses. The characteristic wilt symptoms are a result of colonization and proliferation of the pathogens in the xylem vessels, which undergo fluctuations in osmolarity. To gain insights into the mechanisms that confer the organisms pathogenicity and enable them to proliferate in the unique ecological niche of the plant vascular system, we sequenced the genomes of both Verticillium wilt pathogens and compared them to each other, and with the proteome of Fusarium oxysporum, another fungal wilt pathogen. Our analyses identified a set of proteins that are uniquely shared among all three wilt pathogens, including homologs of a bacterial glucosyl transferase that synthesizes osmoregulated periplasmic glucans and plays important roles in pathogenicity. The acquisition of these genes through horizontal transfer events from Rhizobiales bacteria likely contributed to the niche adaption of these wilt fungi. The Verticillium genomes encode more pectin degrading enzymes and other carbohydrate active enzymes than do all other fungal genomes examined, suggesting an extraordinary capacity to degrade plant pectin barricades. The high level of synteny between the two Verticillium assemblies highlighted four flexible genomic islands in V. dahliae that are enriched for transposable elements, and contain duplicated genes, and genes of potential importance in signaling/transcriptional regulation and iron/lipid metabolism. Coupled with its enhanced capacity to degrade plant materials, these genomic islands may contribute to the increased genetic plasticity and virulence of V. dahliae. Significantly, our study reveals insights into the niche adaptation of fungal wilt pathogens, and advances our understanding of the evolution and development of their pathogenesis.