Fungal endophytes are symbiotic microorganisms that are often found in asymptomatic plants. This study describes the genetic diversity of the fungal endophytes isolated from the roots of plants sampled on the west coast of Korea. Five halophytic plant species, Limonium tetragonum, Suaeda australis, Suaeda maritima, Suaeda glauca Bunge, and Phragmites australis, were collected from the Gochang salt marsh in Korea and used for the isolation and identification of culturable, root-associated endophytic fungi. The fungal internal transcribed transcribe spacer (ITS) region, ITS1-5.8S-ITS2, was used as the DNA barcode for the classification of these specimens. In total, 156 isolates of the fungal strains were identified and categorized into 23 genera and two phyla (Ascomycota and Basidiomycota), with Dothideomycetes and Sordariomycetes as the predominant classes. The genus Alternaria accounted for the largest number of strains, followed by Cladosporium and Fusarium. The highest diversity index was obtained from the endophytic fungal group and associated with the plant P. australis. Waito-C rice seedlings were treated with the fungal culture filtrates to analyze their plant growth-promoting capacity. A bioassay of the Sm-3-7-5 fungal strain isolated from S. maritima confirmed that it had the highest plant growth-promoting capacity. Molecular identification of the Sm-3-7-5 fungal strain revealed that it belonged to Alternaria alternata, and this fungal strain was confirmed to be a producer of gibberellins. These findings provided a fundamental basis for understanding the symbiotic interactions between plants and fungi.

中文翻译：

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从耐盐植物中分离的真菌内生菌的多样性和植物生长促进作用。

真菌内生菌是共生微生物，通常存在于无症状植物中。本研究描述了从韩国西海岸取样的植物根部分离出的内生真菌的遗传多样性。五种盐生植物，Limonium tetragonum、Suaeda australis、Suaeda maritima、Suaeda glauca Bunge和Phragmites australis, 是从韩国高昌盐沼收集的，用于分离和鉴定可培养的根相关内生真菌。真菌内部转录转录间隔区 (ITS) ITS1-5.8S-ITS2 用作对这些标本进行分类的 DNA 条形码。总共鉴定了 156 株真菌菌株，并将其分为 23 个属和两个门（子囊菌门和担子菌门），其中以 Dothideomycetes 和 Sordariomycetes 为主要类别。链格孢菌属占菌株数量最多，其次是枝孢菌属和镰刀菌属。最高的多样性指数来自内生真菌群，与植物P. australis相关. 用真菌培养滤液处理 Waito-C 水稻幼苗，以分析它们的植物生长促进能力。从S. maritima分离的 Sm-3-7-5 真菌菌株的生物测定证实它具有最高的植物生长促进能力。Sm-3-7-5真菌菌株的分子鉴定表明它属于Alternaria alternata，并且该真菌菌株被证实是赤霉素的生产者。这些发现为理解植物和真菌之间的共生相互作用提供了基础。