Diaporthe species occurring on Lithocarpus glabra in China, with descriptions of five new species

•Five new species have been recorded from Lithocarpus glabra.•Results show a high species diversity of Diaporthe from L. glabra.•Host association is proved not reliable for Diaporthe species delimitation.•Three combinations have been made for three Phomopsis species.

The Diaporthe species include important plant pathogenic fungi with wide host ranges and geographic distributions. In this paper, species associated with Lithocarpus glabra were examined using a multi-locus phylogeny based on a combined rDNA-internal transcribed spacer (ITS), and partial translation elongation factor 1-alpha (TEF1), beta tubulin (TUB), and calmodulin (CAL) regions. The phylogenies inferred from combined multi-locus sequences grouped isolates from L. glabra into seven distinct lineages with high branch support, which corresponded to two previously described species and five novel species described in this paper. Our results indicate a high species diversity of Diaporthe associated with L. glabra, and host association is further proved not reliable for species delimitation. Three species previously described in Phomopsis were transferred to Diaporthe in the present paper. A synopsis of morphological characters of the 14 species currently known from Fagaceae is provided.