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Ice-free areas are habitats for most of Antarctica's terrestrial biodiversity. Although fungal communities are an important element of these habitats, knowledge of their assemblages and ecological functions is still limited. Herein, we investigated the diversity, composition, and ecological functionality of fungal communities inhabiting sediments from ice-free areas across pristine and anthropogenically impacted sites in the Fildes Peninsula on King George Island, Antarctica. Samples were collected from both pristine and disturbed areas. We used the internal transcribed spacer (ITS1) region via Illumina sequencing of 34 sediment samples for fungal identification. The Ascomycota (14.6%) and Chytridiomycota (11.8%) were the most dominant phyla, followed by Basidiomycota (8.1%), Rozellomycota (7.0%), Mucoromycota (4.0%), while 34.9% of the fungal diversity remained unidentified. From a total of 1073 OTUs, 532 OTUs corresponded to 114 fungal taxa at the genus level, and 541 OTUs remained unassigned taxonomically. The highest diversity, with 18 genera, was detected at site A-3. At the genus level, there was no preference for either pristine or disturbed sites. The most widely distributed genera were Betamyces (Chytridiomycota), occurring in 29 of the 34 sites, and Thelebolus (Ascomycota), detected in 8 pristine sites and 7 disturbed sites. The Glomeraceae gen. incertae sedis was more common in disturbed sites. A total of 23 different ecological guilds were recorded, with the most abundant guilds being undefined saprotrophs, plant pathogens, plant saprotrophs, pollen saprotrophs, and endophytes. The fungal communities did not show significant differences between pristine and disturbed sites, suggesting that the anthropogenic impact is either not too intense or prolonged, that the spatial distance between the sampled sites is small, and/or that the environmental factors are similar. Although our study revealed a high fungal diversity with various ecological specializations within these communities, nearly one-third of the diversity could not be assigned to any specific taxonomic category. These findings highlight the need for further taxonomic research on fungal species inhabiting ice-free areas. Without identifying the species present, it is difficult to assess potential biodiversity loss due to environmental changes and/or human activities., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2025 Garnica et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: Piscirickettsia salmonis , the causative agent of Piscirickettsiosis, poses a significant threat to the Chilean aquaculture industry, resulting in substantial economic losses annually. The pathogen, first identified as specie in 1992, this pathogen was divided into two genogroups: LF-89 and EM-90, associated with different phenotypic mortality and pathogenicity. Traditional genotyping methods, such as multiplex PCR, are effective but limited by their cost, equipment requirements, and the need for specialized expertise., Methods: This study validates Loop-mediated Isothermal Amplification (LAMP) as a rapid and specific alternative for diagnosing P. salmonis infections. We developed the first qPCR and LAMP assay targeting the species-conserved tonB receptor gene ( ton B-r, WP_016210144.1) for the specific species-level identification of P. salmonis . Additionally, we designed two genotyping LAMP assays to differentiate between the LF-89 and EM-90 genogroups, utilizing the unique coding sequences Nitronate monooxygenase (WP_144420689.1) for LF-89 and Acid phosphatase (WP_016210154.1) for EM-90., Results: The LAMP assays demonstrated sensitivity and specificity comparable to real-time PCR, with additional benefits including rapid results, lower costs, and simplified operation, making them particularly suitable for field use. Specificity was confirmed by testing against other salmonid pathogens, such as Renibacterium salmoninarum, Vibrio ordalii, Flavobacterium psychrophilum, Tenacibaculum maritimum , and Aeromonas salmonicida , with no cross-reactivity observed., Discussion: The visual detection method and precise differentiation between genogroups underscore LAMP's potential as a robust diagnostic tool for aquaculture. This advancement in the specie detection (qPCR and LAMP) and genotyping of P. salmonis represents a significant step forward in disease management within the aquaculture industry. The implementation of LAMP promises enhanced disease surveillance, early detection, and improved management strategies, ultimately benefiting the salmonid aquaculture sector., Competing Interests: JM-S was employed by Mowi Chile S.A. FA and AY were employed by Greenvolution SpA. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Isla, Aguilar, Flores-Martin, Barrientos, Soto-Rauch, Mancilla-Schulz, Almendras, Figueroa and Yañez.)