INTRODUCTION

Endophytic fungi are symbiotic with plants [1]. They live in plant tissues without causing diseases [2]. These fungi chemically defend their host plants against herbivores, insects, and external pathogens [3,4]. Additionally, they enhance the host plants’ resistance to environmental stressors [5]. Endophytic fungi form symbiotic relationships with a range of plants across different climatic zones [6,7]. Their presence is noted in almost all plants, including bryophytes, ferns, conifers, evergreen broad-leaved trees, and deciduous broad-leaved trees [8-12]. These fungi colonize a variety of plant tissues, from vegetative organs, such as roots, stems, and leaves, to reproductive organs, such as flowers and fruits [7]. The relative abundance, species diversity, and community structure of endophytic fungi can vary based on the specific plant tissue [13,14].

Taxus cuspidata Siebold et Zucc. is an evergreen coniferous tree that is geographically distributed in the Far East of Russia, northeastern China, Japan, the Korean Peninsula, and Jeju Island. T. cuspidata grows at altitudes ranging from 700 to 2,500 meters above sea level from Mt. Sungjeoksan in North Korea to Mt. Hallasan on Jeju Island, South Korea [15]. Various tissues of T. cuspidata such as the stem bark, root bark, fibrous roots, twigs, and leaves, produce the anticancer substance taxol (paclitaxel) [16]. Furthermore, endophytic fungi, such as Pestalotiopsis spp. isolated from T. cuspidata, have been shown to produce taxol [17,18].

In this study, we isolated and identified the endophytic fungal strains from T. cuspidata inhabiting Yeongsil area in Mt. Hallasan, Jeju Island. We attempted to confirm the species diversity and community structure according to the plant tissue parts from where the endophytic fungi were isolated.

MATERIAL AND METHODS

RESULTS AND DISCUSSION

We isolated a total of 98 endophytic fungal strains from the needle leaves and twigs of T. cuspidata. Molecular identification revealed 49 fungal species across 33 genera (Fig. 1). From needle leaves, 12 species representing 10 genera were isolated, while from the twigs, 43 species from 29 genera were isolated (Table 1).

Among the isolated endophytes, only Ceratobasidium sp. belonged to the phylum Basidiomycota, and all other species belonged to the phylum Ascomycota. Six species (Cyanodermella asteris, Daldinia childiae, Nemania diffusa, N. serpens, Phomopsis juglandina, and Trichoderma atroviride) were isolated from both needle leaves and twigs. The remaining species were isolated only from either needle leaves or twigs (Fig. 1). Among the species isolated from needle leaves, N. diffusa showed the highest relative abundance at 21.05%. In twigs, Diaporthe eres showed the highest relative abundance of 10.13%. This suggests that the endophytic fungal communities in needle leaves and twig have distinct species composition, indicating that the plant tissue sites can influence the structure of endophytic fungal community [23].

Of the fungal species isolated, two had not been previously unrecorded in Korea. We describe the morphological characteristics and phylogenetic analysis results for these two fungal strains.

Table