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, through the Community Sequencing Program sponsored by the U.S. DOE-Joint Genome Institute. The 9x M. graminicola sequencing is complete and was made public November 1, 2006 following automated and manual annotation. Due to the very good assembly statistics as well as a >2000-marker DArT linkage map that was aligned to the genome, JGI decided to finish the M. graminicola genome at the Stanford Human Genome Center. The majority of chromosomes have been sequenced completely including both telomeres. These data indicate that M. graminicola has both the largest chromosome number and the smallest chromosome sizes recorded among filamentous ascomycetes. The M. fijiensis EST sequencing has resulted in more than 30,000 ESTs and the genome sequencing is currently at approximately 2.5x, which enabled us to revise the genome size estimate of M. fijiensis to approximately 68 Mb, which is 70% larger than that for M. graminicola. The current status of both sequencing projects will be discussed. (Texte integral)