Abstract
Mangrove ecosystems are biodiversity hotspots and vital carbon sinks, yet their fungal communities-key drivers of nutrient cycling and ecosystem resilience-remain largely unexplored in the Neotropics. This is particularly true for Ecuador's protected reserves, where no molecular census of sediment fungi exists. To address this gap, we conducted the first metabarcoding survey of the fungal microbiome in the sediments of the Reserva Ecológica Manglares Churute (REMC), a critical mangrove habitat under increasing anthropogenic pressure. This is the first molecular study to characterize fungal communities in the mangrove sediments of the Reserva Ecológica Manglares Churute (REMC) in the neotropical context of Ecuador, using metabarcoding. The fungal community was dominated by Ascomycota (68%) and Basidiomycota (30%), with minor contributions from Mortierellomycota, Chytridiomycota, and Mucoromycota (<0.1%), and 2.10% unclassified at the phylum level. The most diverse sample (2005L2-69) had a Shannon index of 2.166. Rarefaction curves indicated that additional sampling could reveal more fungal diversity. Fungal assemblages were similar across samples, with minor variations linked to environmental factors. Predominant classes included Dothideomycetes, Agaricomycetes, and Eurotiomycetes. At the genus level, Ascochyta (27%), Antrodia (24%), and Talaromyces (17%) were the most abundant. The presence of genera such as Talaromyces and Penicillium highlights their biotechnological potential, like antibacterial properties. At the same time, the abundance of Ascochyta, a phytopathogen, suggests potential stress or disease susceptibility in this area of REMC. This research provides an essential preliminary overview of the mycobiome in this underexplored region and identifies principal taxa of ecological and biotechnological importance. Furthermore, this investigation, conducted in a specific area of REMC sediments, employs metabarcoding analysis utilizing ITS86-ITS4 primers in Neotropical mangroves, thereby contributing to the global understanding of mangrove microbiomes.