A revision of the family Cucurbitariaceae with additional new taxa from forest trees in Iran

The family Cucurbitariaceae is rich in species diversity and has a wide host range and geographic distribution. In this study, we identified 12 Cucurbitariaceae isolates which were obtained from disease symptoms in two forest trees in Khuzestan province, Iran. In addition, this family is reassessed using phylogenetic analyses based on DNA sequences from five nuclear regions (ITS, LSU, TUB2, TEF1α, and RPB2). The phylogenetic analyses showed that the present isolates represent one new genus, Nothocucurbitaria, and three new species, Allocucurbitaria galinsogisoli, Nothocucurbitaria izehica, and Parafenestella quercicola, which are described and illustrated. Furthermore, the genus Allocucurbitaria is emended to accommodate Seltsamia ulmi that grouped with the type species of Allocucurbitaria. Parafenestella pittospori and A. prunicola are recombined into the genera Neocucurbitaria and Nothocucurbitaria, respectively. Comparative analysis of single-locus trees revealed that the TUB2 and TEF1α can distinguish most genera and species in Cucurbitariaceae, while the ITS and LSU phylogenies show low resolution at both generic and species level. The best single-locus marker, RPB2, was able to distinguish all generic and most species lineages in Cucurbitariaceae.