Diaporthe species are known as endophytes, saprobes and pathogens infecting a wide range of plants and resulting in important crop diseases. In the present study, four strains of Diaporthe were obtained from diseased leaves of Bauhinia variegata in Guangdong Province, China. Phylogenetic analyses were conducted to identify these strains using five gene regions: internal transcribed spacer (ITS), calmodulin (cal), histone H3 (his3), translation elongation factor 1-α (tef1) and β-tubulin (tub2). The results combined with morphology revealed two new species of Diaporthe named D. bauhiniicola in D. arecae species complex and D. guangzhouensis in D. sojae species complex.

Diaporthales is a significant fungal order comprising species that predominantly inhabit plant tissues, being pathogens, endophytes, and saprobes. Recent studies have uncovered extensive species diversity across various hosts, utilizing both morphological characteristics and molecular phylogenetic analyses. In this study, samples of leaf spots and branch cankers were collected from China, and fungal isolations were established. Species identification was conducted using a phylogenetic approach based on combined sequence data from the internal transcribed spacer (ITS) region, large subunit ribosomal DNA (LSU), the DNA-directed RNA polymerase II second largest subunit (rpb2), and translation elongation factor 1-alpha (tef1) genes, together with morphological observations. As a result, the novel genus Tiania is proposed, with three newly described species: T. chinensis, T. lithocarpicola, and T. quercicola. These species are validated by pairwise homoplasy index (PHI) analysis, ensuring robust support for their distinction. This study explores the rare family Diaporthostomataceae, providing the first descriptions of their anamorphic forms. By offering detailed morphological and molecular data, this research lays a foundation for future taxonomic and systematic studies of the Diaporthales.

Diaporthales is an important fungal order comprising plant-associated pathogens, endophytes, and saprobes in commercial crops and forest trees. Over the past decades, utilizing multiple gene phylogeny has substantially advanced our understanding of taxonomic relationships within this order, leading to the recognition of 35 morphologically and molecularly well-supported families. Among these, Pseudoplagiostoma (Pseudoplagiostomataceae) and Pyrispora (Pyrisporaceae) form two phylogenetically closely related lineages that exhibit distinct morphological characteristics. In this study, we conducted comprehensive morphological and phylogenetic analyses of fungal specimens associated with Fagaceae hosts and proposed four new species and two new combinations: Ps. fagaceaearumsp. nov., Ps. neocastanopsidissp. nov., Ps. quercussp. nov., Py. humiliscomb. nov., Py. myracrodruoniscomb. nov., and Py. quercicolasp. nov. Furthermore, based on detailed morphological comparisons and molecular evidence, we synonymized Neoplagiostoma with Pyrispora, Ps. castaneae and N. castaneae with Py. castaneae, Ps. ilicis with Ps. wuyishanense and Ps. diaoluoshanense with Ps. mangiferae. This study provides substantial morphological and molecular data that significantly contribute to our understanding of Pseudoplagiostomataceae and Pyrisporaceae, thereby establishing a robust foundation for future taxonomic revisions and systematic investigations within Diaporthales. The findings not only expand our knowledge of fungal diversity associated with Fagaceae but also enhance our comprehension of evolutionary relationships within these important fungal families.

The genus Dendrostoma is known to inhabit tree barks associated with branch canker diseases in China and several countries of Europe. Previous studies indicated that species of Dendrostoma prefer inhabiting fagaceous hosts, especially species of Castanea. In the present study, we obtained four isolates from cankered branches of Chinese chestnut (C. mollissima) in Rizhao City, Shandong Province, China. Morphological comparisons and phylogenetical analyses of a combined ITS-tef1-rpb2 sequence matrix were conducted, which revealed two new species named Dendrostoma rizhaoensesp. nov. and D. tianiisp. nov. The new taxa are compared with other Dendrostoma species and comprehensive descriptions and illustrations are provided herein.