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Diaporthe species are associated with Citrus as endophytes, pathogens, and saprobes worldwide. However, little is known about Diaporthe as endophytes in Citrus grandis in China. In this study, 24 endophytic Diaporthe isolates were obtained from cultivated C. grandis cv. "Tomentosa" in Huazhou, Guangdong Province in 2019. The nuclear ribosomal internal transcribed spacer (ITS), partial sequences of translation elongation factor 1-α ( tef1 ), β-tubulin ( tub2 ), and partial calmodulin ( cal ) gene regions were sequenced and employed to construct phylogenetic trees. Based on morphology and combined multigene phylogeny, eleven Diaporthe species were identified including two new species, Diaporthe endocitricola and D. guangdongensis . These are the first report of D. apiculata , D. aquatica , D. arecae , D. biconispora , D. limonicola , D. masirevicii , D. passifloricola, D. perseae , and D. sennae on C. grandis . This study provides the first intensive study of endophytic Diaporthe species on C. grandis cv. tomentosa in China. These results will improve the current knowledge of Diaporthe species associated with C. grandis . The results obtained in this study will also help to understand the potential pathogens and biocontrol agents and to develop a platform in disease management., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Dong, Manawasinghe, Huang, Shu, Phillips, Dissanayake, Hyde, Xiang and Luo.)

Grapevine trunk diseases have become one of the main threats to grape production worldwide, with Diaporthe species as an emerging group of pathogens in China. At present, relatively little is known about the taxonomy and genetic diversity of Chinese Diaporthe populations, including their relationships to other populations worldwide. Here, we conducted an extensive field survey in six provinces in China to identify and characterize Diaporthe species in grape vineyards. Ninety-four isolates were identified and analyzed using multi-locus phylogeny. The isolates belonged to eight species, including three novel taxa, Diaporthe guangxiensis (D. guangxiensis), Diaporthe hubeiensis (D. hubeiensis), Diaporthe viniferae (D. viniferae) , and three new host records, Diaporthe gulyae (D. gulyae), Diaporthe pescicola (D. pescicola) , and Diaporthe unshiuensis (D. unshiuensis) . The most commonly isolated species was Diaporthe eres (D. eres) . In addition, high genetic diversity was observed for D. eres in Chinese vineyards. Haplotype network analysis of D. eres isolates from China and Europe showed a close relationship between samples from the two geographical locations and evidence for recombination. In comparative pathogenicity testing, D. gulyae was the most aggressive taxon, whereas D. hubeiensis was the least aggressive. This study provides new insights into the Diaporthe species associated with grapevines in China, and our results can be used to develop effective disease management strategies.