The polyphyletic nature of Pleosporales: an example from Massariosphaeria based on rDNA and RBP2 gene phylogenies.

Massariosphaeria is a loculoascomycetous fungus currently accommodated within the Pleosporales. However, based on morphology alone, it has been difficult to assess its familial position and its affinities to other fungi with bitunicate asci. In order to establish its evolutionary relationships, two regions of the rDNA (18S and 28S) and two regions of the RPB2 protein-coding gene were sequenced and analysed phylogenetically. Multigene phylogenies revealed that Massariosphaeria is not monophyletic and results are in disagreement with existing morphological-based classification schemes. Characters, such as ascomatal shape and ascospore morphology, have evolved more than once within the Pleosporales. The familial placement of several species is still obscure, except M. grandispora, which could be confidently assigned to the Lophiostomaceae. M. typhicola is closely related to Trematosphaeria hydrela (Melanommataceae), whereas M. triseptata is related to Melanomma radicans but shares close affinities to the Sporormiaceae. The placement of M. roumeguerei is still unresolved, and it does not appear to have any close evolutionary relationship to any known melanommataceous or pleosporaceous genera. Our molecular data also refute the monophyly of Kirschsteiniothelia, Massarina, Melanomma, and Pleospora, and support previous phylogenetic hypotheses that Melanommataceae is polyphyletic. There is a need for more phylogenetic (and taxonomic) studies within the Pleosporales, especially incorporation of more anamorphic taxa and type species.