Genomic and Comparative Analysis of the Class Dothideomycetes

Abstract

The class Dothideomycetes (Schoch et al. 2009) is a recently defined taxon within the phylum Ascomycota, with approximately 20,000 member species. Many species are important phytopathogens employing diverse pathogenicity strategies. This review compares the currently available genome sequences, including their mitochondrial sequences. The genomes of Dothideomycetes exhibit remarkable plasticity, characterised by extensive rearrangement of gene order and orientation. Dothideomycetes also display the ability to take advantage of repeat induced point mutation (RIP), a fungal specific mechanism to protect their genomes against transposon invasion. RIP also affects areas of the genome adjacent to transposon insertion sites conferring the adaptive advantage of rapid generation of diversity in fungal pathogenicity effector genes. In addition, Dothideomycetes have the propensity for lateral gene transfer which can involve the transmission of pathogenicity effectors. The combination of these mechanisms has led to the ascendance of many Dothideomycetes as the dominant fungal pathogens of their cultivated host plant species.