Five New Phyllachora Species from Tar Spot Fungi on Poaceae in Sichuan China.

Abstract

Tar spot is a prevalent fungal disease characterized by shiny black spots on the leaves, stems, and fruits of various plants. It is typically caused by members of the family Phyllachoraceae, which consists of biotrophic and obligate plant parasitic fungi. During field investigations of tar spot fungi in Sichuan Province, China, 70 fungal samples associated with tar spots belonging to the family Poaceae were collected from 13 different locations. Through morphological studies and multi-locus phylogenetic analysis of combined ITS, SSU, and LSU datasets, the collected samples were classified into eight Phyllachora species. Among these, five were identified as new species (Phyllachora cylindricae, P. festucae, P. luzhouensis, P. palmifoliae, and P. wenchuanensis), and two represented new host records (P. chongzhouensis, P. panicicola). The new species are accompanied by descriptions and illustrations, while their characteristics are discussed in relation to comparable taxa. Additionally, P. yuanjiangensis is synonymized under P. xinpingensis. These findings enhance our understanding of tar spot fungi in Sichuan and, given that Phyllachora species are important pathogens of plants in the Poaceae family, establish a foundation for further research to better understand their potential impacts on agriculture and the local ecology.