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

A high diversity of culturable foliar endophytic fungi is known from various mangrove plants, and the core taxa include species from , , , , , 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 var. 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. (10.58%, percentage of occurrence), sp. 3 (7.69%) and sp. (7.69%) were dominant in the winter samples; (13.13%), (10.10%) and sp. 1 (9.09%) in the summer samples. Overall, (6.90%), (6.40%) and 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 sp. (3.46%), (2.56%) and (1.41%) in the winter leaves, and sp. (10.72%), sp. (7.90%), (3.45%) and (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 var. . Many of the fungi identified were plant pathogens and may eventually cause diseases in the host.