Endophytic Fungi Isolated from the Marine Macroalga Dictyopteris pacifica in Korea

Abstract

The exploration of endophytic fungi associated with seaweeds has garnered significant interest due to their crucial ecological functions and potential as sources of valuable bioactive compounds. In this study, we isolated and identified endophytic fungi from the brown seaweed Dictyopteris pacifica, collected from the intertidal zone of Yeongdoek, Gyeongsangbuk-do in Korea. Through morphological examination and molecular phylogenetic analysis using multiple molecular markers, including ITS, LSU, SSU, TEF1, TUB2, and RPB2 sequences, we identified three fungal species not previously recorded in Korea: Emericellopsis fuci, Neoarthrinium lithocarpicola, and Periconia chimonanthi. Detailed descriptions of morphological characteristics and phylogenetic analyses are provided. This study represents the first report of these endophytic fungi isolated from D. pacifica in Korea, thereby enhancing the understanding of the diversity of seaweed-associated endophytic fungi in the region.

Keywords: Dictyopteris pacifica; endophytic fungi; macro algae; seaweed.

Figure 1.

Maximum likelihood tree of Emericellopsis fuci KNUE 24S071. The tree is based on concatenated sequences of internal transcribed spacer (ITS), large subunit ribosomal RNA (LSU), RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-alpha (TEF1) DNA sequences. Stanjemonium dichromosporum was used as an outgroup. The numbers on the nodes represent bootstrap values greater than 50% (1,000 replicates).

Figure 2.

Maximum likelihood tree of Neoarthrinium lithocarpicola KNUE 24S082. The tree is based on concatenated sequences of internal transcribed spacer (ITS), large subunit ribosomal RNA (LSU), beta-tubulin (TUB2) DNA sequences. Pestalotiopsis australasiae was used as an outgroup. The numbers on the nodes represent bootstrap values greater than 50% (1,000 replicates).

Figure 3.

Maximum likelihood tree of Periconia chimonanthi KNUE 24S115. The tree is based on concatenated sequences of internal transcribed spacer (ITS), large subunit ribosomal RNA (LSU), small subunit ribosomal RNA (SSU), translation elongation factor 1-alpha (TEF1) DNA sequences. Lentithecium aquaticum was used as an outgroup. The numbers on the nodes represent bootstrap values greater than 50% (1,000 replicates).

Figure 4.

Morphology of Emericellopsis fuci KNUE 24S071. A-B Colony after 7 days of growth at 25 °C. The left side shows the front view and the right side shows reverse view, on malt extract agar (A) and potato dextrose agar (B). C-G: Microscopic features of phialides and conidia. C: Phialides of varying lengths. D: Longer phialides. E: Conidiogenous occurring in the phialide. F: Conidia with diverse sizes and shapes. G: Larger conidia. Scale bars: C-E = 20 μm, F-G: 10 μm.

Figure 5.

Morphology of Neoarthrinium lithocarpicola KNUE 24S082. A-B Colony after 7 days of growth at 25 °C. The left side shows the front view and the right side shows reverse view, on malt extract agar (A) and potato dextrose agar (B). C-G: Microscopic features of phialides and conidia. C: Conidiogenous cell bearing conidia. D, E: Conidiophores with attached conidia. F, G: Conidia showing diverse shapes. Scale bars = 10 μm.

Figure 6.

Morphology of Periconia chimonanthi KNUE 24S115. A-B Colony after 7 days of growth at 25 °C. The left side shows front view and the right side shows reverse side, on malt extract agar (A) and potato dextrose agar (B). C-G: Microscopic features of conidiogenous and conidia. C: Conidiogenous cells with developing conidia in short chains. D: Polyblastic and variously shaped conidiogenous cells. E: Immature hyaline conidiogenous cells. F-G: Conidia with hyphae. Scale bars: (C, F, G)=10 μm, (D, E)=20 μm.