Determination of endophytic mycobiota in leaves of Anatolian sweetgum tree (Liquidambar orientalis Mill.)

Endophytic fungi generally live within plant tissues without causing harm, but some can become pathogenic under stress conditions. They enhance plant resistance to stress and pests, supporting ecosystem health, and serve as natural alternatives to chemical pesticides in biocontrol. Additionally, as potential sources for the production of bioactive compounds, they hold great promise in biotechnological research. In this study, fungal endophytes were isolated from the leaves and petioles of Liquidambar orientalis Mill., a woody plant endemic to Türkiye with high economic value. Plant materials were collected from 10 different sampling sites within Muğla province in September 2023. As a result of the isolations, 499 fungal isolates were obtained and assigned to 38 different morphological groups. Representative isolates from each morphological group were subjected to DNA isolation, followed by PCR reactions targeting the ITS (Internal Transcribed Spacer) and beta-tubulin gene regions. All fungi belong to the Ascomycota phylum, with a total of 37 fungal groups identified across 15 different families, including 11 genera and 26 species. Among the fungal groups obtained, a previously unrecorded species was identified. The most common families were Diaporthaceae (%34.86), Pleosporaceae (%23.44), and Botryosphaeriaceae (%22.24). The most common and dominant species were Diaporthe eres (%15.03), Phomopsis sp. (%12.42), and Alternaria sp. (%11.22). Fungal diversity analyses, including Shannon and Simpson alpha diversity indices, Chao1 index, and species richness, revealed statistically significant variations based on spatial, individual, directional, tissue type, tissue region, and medium-related factors. This study represents the first report of endophytic fungi associated with L. orientalis, marking a significant contribution to the knowledge of this species. Furthermore, the species Alternaria destruens, Alternaria alstroemeriae, Stemphylium majusculum, Diaporthe cynaroidis, Pseudopithomyces rosae, Nothophoma variabilis, Cladosporium endophyticum, Cladosporium colombia, Muyocopron sp., Sphaerulina rhododendricola, Constantinomyces macerans, and Aequabiliella effusa are reported for the first time in Türkiye.