Réblová Martina, Nekvindová Jana, Hynar Ondřej, Vohník Martin
Department of Taxonomy, Institute of Botany, Czech Academy of Sciences, Zámek 1, Průhonice, Czech Republic.
Institute of Clinical Biochemistry and Diagnostics, University Hospital Hradec Králové, Sokolská 581, Hradec Králové, Czech Republic.
IMA Fungus. 2025 Aug 12;16:e157688. doi: 10.3897/imafungus.16.157688. eCollection 2025.
As part of an ongoing study of marine fungi associated with seagrasses, we discovered a novel root-fungus symbiosis in the Indo-Pacific species from Mauritius. Culturing its mycobionts yielded dozens of morphologically and genetically uniform isolates, all representing a previously unknown fungus. A second undescribed fungus was isolated from saline soils in Czechia. Phylogenetic analyses based on three rDNA markers confirmed both taxa as distinct, hitherto unknown lineages within the , which are introduced here as and , respectively. Both species developed characteristic structures under culture conditions that enabled their morphological characterisation: forms distinctive clusters of dark brown monilioid hyphae, while is characterised by holoblastic conidiogenesis and solitary, dark brown, multicellular conidia. clustered in a strongly supported clade with , a parasitic genus of the red macroalga , while the closest relatives of were identified as the asexual genera and (nom. inval. Art. 40.7). An analysis of published metabarcoding ITS rDNA data from environmental samples in the GlobalFungi database indicated that is widely distributed across temperate, subtropical, and tropical regions in the Northern and Southern Hemispheres. The species exhibits a strong preference for aquatic biomes, particularly marine and estuarine, with a few records in terrestrial ecosystems. In contrast, no record of was retrieved from GlobalFungi, suggesting narrower ecological specialisation, a close association with its seagrass host, and/or a restricted geographical range. Our findings expand the ecological and phylogenetic scope of the , bridging marine and terrestrial fungal communities, and highlight seagrass roots as an important source of novel symbiotic marine fungi. Recent discoveries of the in saline inland soils challenge their marine exclusivity and raise important questions about their ecological plasticity, dispersal mechanisms, and adaptive strategies. In light of current observations, we discuss the taxonomic challenges of the and the lulworthialean fungi, integrating molecular and morphological perspectives. We address the importance of combining morphological and molecular approaches to accurately delineate new fungal taxa, as well as the value of environmental DNA metabarcoding for uncovering cryptic fungal diversity and enhancing our understanding of fungal distribution and ecological functions.
作为一项正在进行的与海草相关的海洋真菌研究的一部分，我们在来自毛里求斯的印度 - 太平洋物种中发现了一种新的根 - 真菌共生关系。培养其菌根共生体产生了数十个形态和基因均一的分离株，所有这些都代表了一种以前未知的真菌。从捷克的盐渍土壤中分离出了另一种未描述的真菌。基于三个核糖体DNA标记的系统发育分析证实这两个分类单元是不同的，是迄今为止在该目内未知的谱系，在此分别将它们命名为 和 。这两个物种在培养条件下都形成了特征性结构，从而能够对其进行形态学表征： 形成独特的深棕色念珠状菌丝簇，而 的特征是全壁产孢和单个、深棕色、多细胞分生孢子。 与红色大型海藻 的寄生属 在一个得到有力支持的分支中聚类，而 的最亲近亲属被鉴定为无性属 和 （无效名称，第40.7条）。对全球真菌数据库中环境样本已发表的ITS核糖体DNA元条形码数据的分析表明， 在北半球和南半球的温带、亚热带和热带地区广泛分布。该物种对水生生物群落表现出强烈偏好，特别是海洋和河口生物群落，在陆地生态系统中有一些记录。相比之下，在全球真菌数据库中未检索到 的记录，这表明其生态专业化程度更高，与其海草宿主密切相关，和/或地理范围受限。我们的发现扩展了该目的生态和系统发育范围，架起了海洋和陆地真菌群落之间的桥梁，并突出了海草根作为新型共生海洋真菌的重要来源。最近在盐渍内陆土壤中发现 的情况对它们仅存在于海洋中的特性提出了挑战，并引发了关于它们的生态可塑性、传播机制和适应策略的重要问题。鉴于当前的观察结果，我们讨论了该目和鲁尔沃氏菌目真菌的分类学挑战，整合了分子和形态学观点。我们阐述了结合形态学和分子方法准确界定新真菌分类单元的重要性，以及环境DNA元条形码在揭示隐秘真菌多样性和增进我们对真菌分布及生态功能理解方面的价值。
