Sequencing the Major Mycosphaerella Pathogens of Wheat and Banana

Mycosphaerella is one of the largest genera of plant-pathogenic fungi with more than 1,000 named species, many of which are important pathogens causing leaf spotting diseases in a wide variety of crops including cereals, citrus, banana, eucalypts, soft fruits and horticultural crops. A few species of Mycosphaerella cause disease in humans and other vertebrates. An international project was initiated to sequence the genomes of M. graminicola and M. fijiensis, two of the most economically important pathogens of wheat and banana, respectively, along with 40,000 ESTs from M. fijiensis and the related maize pathogen Cercospora zeae-maydis. The 9x M. graminicola genome size is 39.8 Mb with chromosome sizes from 548 kb to 6 Mb and a complete circular mitochondrial genome of 43,947 bp. Our data indicate that M. graminicola has both the largest chromosome number and the smallest chromosome sizes recorded among filamentous ascomycetes. The Mycosphaerella Genomics Consortium, which was established in 2003, decided to use M. graminicola as the model to develop more genetic and genomic research on M. fijiensis. Since 2003, M. fijiensis EST sequencing has resulted in more than 30,000 ESTs, and the genome sequencing was recently finished at 7.8x. The genome size of M. fijiensis is 80