Comparative genomics of the secretome of the Dothideomycete fungus Cladosporium fulvum

The genome size (ca. 70Mb) of the recently sequenced Dothideomycete fungus Cladosporium fulvum, is about twice that of most sequenced fungal genomes including the related fungi Mycosphaerella graminicola and Dothistroma septosporum, but is about the same as that of M. fijiensis. This is mainly due to the high content of sequence repeats (about 40-50%) originating from transposable elements. Bioinformatic analysis revealed that the highest number of effectors homologous to those reported in C. fulvum is found in D. septosporum. To identify additional effectors and to facilitate the genome annotation, we have performed proteome analyses on the secretome of C. fulvum grown in planta and in vitro. We have identified many novel secreted putative effectors including small cysteine-rich proteins, different classes of proteases, specific cell wall hydolyzing enzymes and proteins of unknown function. For a substantial number of C. fulvum secreted proteases intron retention occurs more frequently than in related fungi