A highly diverse fungal community associated with leaves of the mangrove plant Acanthus ilicifolius var. xiamenensis revealed by isolation and metabarcoding analyses

Wei-Chiung Chi; Weiling Chen; Chih-Chiao He; Sheng-Yu Guo; Hyo-Jung Cha; Ling Ming Tsang; Tsz Wai Ho; Ka-Lai Pang

doi:10.7717/peerj.7293

A highly diverse fungal community associated with leaves of the mangrove plant Acanthus ilicifolius var. xiamenensis revealed by isolation and metabarcoding analyses

PeerJ. 2019 Jul 9:7:e7293. doi: 10.7717/peerj.7293. eCollection 2019.

Authors

Wei-Chiung Chi^{1

2}, Weiling Chen¹, Chih-Chiao He¹, Sheng-Yu Guo¹, Hyo-Jung Cha¹, Ling Ming Tsang³, Tsz Wai Ho⁴, Ka-Lai Pang¹

Affiliations

¹ Institute of Marine Biology and Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
² Institute of Food Science, National Quemoy University, Kinmen, Taiwan.
³ School of Biological Science, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR.
⁴ School of Biological Sciences, University of Western Australia, Perth, Australia.

Abstract

A high diversity of culturable foliar endophytic fungi is known from various mangrove plants, and the core taxa include species from Colletotrichum, Pestalotiopsis, Phoma, Phomopsis, Sporomiella, among others. Since a small fraction of fungi is able to grow in culture, this study investigated the diversity of fungi associated with leaves of Acanthus ilicifolius var. xiamenensis using both isolation and metabarcoding approaches. A total of 203 isolates were cultured from surface-sterilized leaves, representing 47 different fungal species: 30 species from the winter samples (104 isolates), and 26 species from the summer samples (99 isolates). Ascomycota was dominant in both types of leaf samples, while Basidiomycota was isolated only from the summer samples. Drechslera dematioidea (10.58%, percentage of occurrence), Colletotrichum sp. 3 (7.69%) and Alternaria sp. (7.69%) were dominant in the winter samples; Fusarium oxysporum (13.13%), Diaporthe endophytica (10.10%) and Colletotrichum sp. 1 (9.09%) in the summer samples. Overall, Corynespora cassiicola (6.90%), F. oxysporum (6.40%) and Guignardia sp. (6.40%) had the highest overall percentage of occurrence. In the metabarcoding analysis, a total of 111 operational taxonomic units (OTUs) were identified from 17 leaf samples: 96 OTUs from the winter and 70 OTUs from the summer samples. Sequences belonging to Ascomycota and Basidiomycota were detected in both samples but the former phylum was dominant over the latter. Based on read abundance, taxa having the highest percentage of occurrence included Alternaria sp. (3.46%), Cladosporium delicatulum (2.56%) and Pyrenochaetopsis leptospora (1.41%) in the winter leaves, and Aureobasidium sp. (10.72%), Cladosporium sp. (7.90%), C. delicatulum (3.45%) and Hortaea werneckii (3.21%) in the summer leaves. These latter four species also had the highest overall percentage of occurrence. Combining the results from both methods, a high diversity of fungi (at least 110 species) was found associated with leaves of A. ilicifolius var. xiamenensis. Many of the fungi identified were plant pathogens and may eventually cause diseases in the host.

Keywords: Culturomics; Endophytes; High throughput sequencing; Illumina sequencing; Terrestrial fungi; rDNA.

Grants and funding

This work was supported by grants from the Center of Excellence for the Oceans (National Taiwan Ocean University), which is financially supported by The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education in Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.