Multigene phylogeny, taxonomy, and potential biological properties of and species (Roussoellaceae, Dothideomycetes) from Asteraceae weeds in northern Thailand.

In our study, dead stems of two Asteraceae species (weeds) were collected from northern Thailand. Both morphology and multigene phylogeny were used to determine the identity of the taxa. Maximum likelihood and Bayesian inference analyses of combined LSU, SSU, ITS, and data revealed two new species , and with one new host record of . Preliminary investigation into antibacterial properties revealed that our three isolates inhibited the growth of , , and . Additionally, we present updated phylogenetic trees for Roussoellaceae, accompanied by detailed descriptions and illustrations of the three identified species.