Phylogenetic relationship and evolution of Neodidymelliopsis isolates collected from Iran

Several isolates of the novel genus Neodidymelliopsis have been recently found in Iranian citrus orchards with severe dieback symptoms. Neodidymelliopsis belongs to Didymellaceae, an important family of Pleosporales, Dothideomycetes. None of the few studies on molecular dating of Ascomycetes have resolved the divergence time of genera in Didymellaceae. Motivated by this fact, we consider the reliable age of a fossil related to extant species of Aigilalus, the estimated mean crown age of Dothideomycetes from other studies as a secondary calibration, also the second fossil which represent common ancestor of Capnodiales to calibrate the reconstructed tree. Our dating analysis is based on four genetic regions of 91 taxa from Capnodiales and Pleosporales, using BEAST analysis. The selected taxa of Pleosporales belong to Aigialaceae and Didymellaceae; including three newly discovered Neodidymelliopsis sp. isolates and one isolate of Didymella sp. from Iran. Our dating analyses suggest that Didymellaceae diverged from Aigialaceae in the Cretaceous, and initial divergence of Didymellaceae happened in the late Eocene followed by two divergences in the late Oligocene and several splits in the Miocene. Furthermore, the results suggest that the Iranian isolates of Neodidymelliopsis sp. and Didymella sp. diverged from other Neodidymelliopsis and Didymella isolates in the Pliocene and the late Miocene, respectively.