Plant & Animal Genomes XV Conference

January 13-17, 2007
Town & Country Convention Center
San Diego, CA

Advances In Genomics Of The Most Important Fungal Banana Pathogen Mycosphaerella fijiensis ( Black Sigatoka)

Andrew C. James , Blondy Canto-Canche , Laura Conde-Ferraez , Cecilia Rodriguez- Garcia , Leticia Peraza-Echeverria , Nestor Raigosa , Gilberto Manzo-Sanchez , Santy Peraza-Echeverria , Ignacio Islas-Flores

  Unidad de Biotecnologia, Centro de Investigacion Cientifica de Yucatan, Calle 43 #130, Col.Churburna de Hidalgo, Merida C.P. 97200, Yucatan, Mexico

Applying a non-sphaeroplasting approach, the electrophoretic karyotype and approximate genome size of Mycosphaerella fijiensis was determined. The karyotype was found to be highly polymorphic with 8 to 13 resolved chromosomes ranging from ca. 0.5 to 8.6 Mb. Minimal genome size was estimated to range from 27 to 35 Mb. Applying a modification of the same technique we have also constructed and characterized a BAC genomic library with a mean insert size of 90 Kb, which represents ca. 4.9 X genome equivalents. Approximately 39 % of the library contains highly repetitive DNA, which is similar to other Ascomycetes. In collaboration with PRI and CBS Holland, the mating type idiomorphs were isolated and cloned. We found inverted regions with high identity within both idiomorphs, suggesting unique inversion events which could have significance in the evolution of this species. Multiplex PCR has been developed to determine mating type for a field analysis. In collaboration with CIRAD France and CINVESTAV México, various crosses between isolates differing in continental origin and / or aggressiveness, have been made. From a selected cross, a total of 61 ascospore progeny were analyzed for segregation with 299 AFLP and 16 SSR markers. With a LOD value of 3.0, twenty three linkage groups were obtained