High species diversity in Diaporthe associated with citrus diseases in China

X E Xiao; Y D Liu; F Zheng; T Xiong; Y T Zeng; W Wang; X L Zheng; Q Wu; J P Xu; P W Crous; C Jiao; H Y Li

doi:10.3767/persoonia.2023.51.06

High species diversity in Diaporthe associated with citrus diseases in China

Persoonia. 2023 Jun:51:229-256. doi: 10.3767/persoonia.2023.51.06. Epub 2023 Nov 27.

Authors

X E Xiao¹, Y D Liu¹, F Zheng¹, T Xiong¹, Y T Zeng¹, W Wang¹, X L Zheng², Q Wu², J P Xu³, P W Crous^{4

5}, C Jiao¹, H Y Li¹

Affiliations

¹ The Key Laboratory of Molecular Biology of Crop Pathogens and Insects of Ministry of Agriculture, The Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
² Quzhou Academy of Agricultural and Forestry Sciences, Quzhou, 324000, China.
³ Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada.
⁴ Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
⁵ Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa.

Abstract

Species in Diaporthe have broad host ranges and cosmopolitan geographic distributions, occurring as endophytes, saprobes and plant pathogens. Previous studies have indicated that many Diaporthe species are associated with Citrus. To further determine the diversity of Diaporthe species associated with citrus diseases in China, we conducted extensive surveys in major citrus-producing areas from 2017-2020. Diseased tissues were collected from leaves, fruits, twigs, branches and trunks showing a range of symptoms including melanose, dieback, gummosis, wood decay and canker. Based on phylogenetic comparisons of DNA sequences of the internal transcribed spacer regions (ITS), calmodulin (cal), histone H3 (his3), translation elongation factor 1-alpha (tef1) and beta-tubulin (tub2), 393 isolates from 10 provinces were identified as belonging to 36 species of Diaporthe, including 32 known species, namely D. apiculata, D. biconispora, D. biguttulata, D. caryae, D. citri, D. citriasiana, D. compacta, D. discoidispora, D. endophytica, D. eres, D. fusicola, D. fulvicolor, D. guangxiensis, D. hongkongensis, D. hubeiensis, D. limonicola, D. litchii, D. novem, D. passifloricola, D. penetriteum, D. pescicola, D. pometiae, D. sackstonii, D. sennicola, D. sojae, D. spinosa, D. subclavata, D. tectonae, D. tibetensis, D. unshiuensis, D. velutina and D. xishuangbanica, and four new species, namely D. gammata, D. jishouensis, D. ruiliensis and D. sexualispora. Among the 32 known species, 14 are reported for the first time on Citrus, and two are newly reported from China. Among the 36 species, D. citri was the dominant species as exemplified by its high frequency of isolation and virulence. Pathogenicity tests indicated that most Diaporthe species obtained in this study were weakly aggressive or non-pathogenic to the tested citrus varieties. Only D. citri produced the longest lesion lengths on citrus shoots and induced melanose on citrus leaves. These results further demonstrated that a rich diversity of Diaporthe species occupy Citrus, but only a few species are harmful and D. citri is the main pathogen for Citrus in China. The present study provides a basis from which targeted monitoring, prevention and control measures can be developed. Citation: Xiao XE, Liu YD, Zheng F, et al. 2023. High species diversity in Diaporthe associated with citrus diseases in China. Persoonia 51: 229-256. doi: 10.3767/persoonia.2023.51.06.

Keywords: Citrus diseases; Diaporthe; new taxa; pathogenicity; phylogenetic analysis.