Two novel species of Mesophoma gen. nov. from PR China and a potential biocontrol of the invasive weed Ageratina adenophora

Abstract During an investigation of the fungal pathogens associated with the invasive weed Ageratina adenophora from China, some interesting isolates were collected. Among them, a novel genus Mesophoma containing two novel species, M. speciosa and M. ageratinae, from healthy leaf, leaf spot, and roots of Ag. adenophora was found. Phylogenetic analysis of the combined the internal transcribed spacer (ITS), large nuclear subunit ribosomal DNA (LSU), the RNA polymerase II second largest subunit (rpb2), and the partial β-tubulin (tub2) sequences showed that M. speciosa and M. ageratinae each formed a distinct clade, separating from all genera previously described in Didymellaceae. Combined morphological characters allowed us to describe them as novel species belonging to a novel genus Mesophoma. The full descriptions, illustrations, and a phylogenetic tree showing the position of M. speciosa and M. ageratinae were provided in this study. The potential for these strains to be developed into a biocontrol for the spread of the invasive weed Ag. adenophora was also discussed.