Comparative genomics of the Sigatoka disease complex on banana indicates a direct link between pathogen emergence and nutritional virulence.
I. STERGIOPOULOS (1), T. Chang (1), A. Salvucci (1), P. Crous (2) (1) University of California Davis, U.S.A.; (2) CBS-KNAW Fungal Biodiversity Centre, Netherlands

Understanding the evolutionary and genomic changes involved in the emergence of new pathogens and shifts in their virulence spectra after speciation is critical. Such knowledge is vital for deciphering the biological process of disease and for designing new disease control methods. In order to understand the evolutionary trends and genomic modifications associated with speciation and virulence-jumps in fungi, we have sequenced the 82.8 Mb and 53.8 Mb genomes of Pseudocercospora musae and P. eumusae, respectively and compared them with the 74.1 Mb genome sequence of P. fijiensis. The three species constitute the Sigatoka disease complex of banana, currently the most destructive disease in this crop. However, despite their common ancestry and shared host-specificity, they show clear differences in virulence with P. fijiensis and P. eumusae being the most aggressive. Our comparative genomic and evolutionary analyses revealed that changes in gene family sizes among the three species are not selectively neutral but more respectful of the species virulence profiles rather than their evolutionary relationships. Specifically, P. eumusae and P. fijiensis share convergent patterns of expansions and contractions in core gene families related to metabolism and degradation of plant cell walls, suggesting that virulence-jumps and speciation in these fungi are to a certain extent linked to recurrent genomic changes in molecular pathways associated with nutrient acquisition and assimilation.

Abstract Number: P12-401
Session Type: Poster