Metabarcoding Reveals Fungal Diversity in the Root and Rhizosphere of Isoëtes cangae : An Endemic and Endangered Amazonian Species

The roots of most plants worldwide are associated with diverse fungal communities present in the soil. This study provides a descriptive assessment of the fungal diversity associated with the roots and rhizosphere of Isoëtes cangae , an endangered species endemic to the Amazon. Two sampling campaigns were conducted during the rainy and dry seasons, with four adult individuals sampled per season along the southern margin of Amendoim Lake, Serra dos Carajás, Pará State, Brazil. Fungal community characterization was performed using an ITS amplicon metabarcoding approach on the Illumina HiSeq platform. A total of 31 fungal taxa were identified at the species level. The detected taxa included fungi commonly reported in the literature with different ecological lifestyles, such as saprotrophic and phytopathogenic groups. The most abundant phyla in both seasons were Ascomycota, Mucoromycota, and Glomeromycota. Alpha and principal coordinates analysis (PCoA) did not reveal statistically significant differences, indicating no significant variation in fungal diversity within or between seasons. Additionally, a high proportion of unclassified amplicon sequence variants (ASVs) was observed, highlighting gaps in reference databases and emphasizing the baseline nature of this study on fungal communities associated with the roots and rhizosphere of I. cangae .