Fungal Diversity and Community Structure in Soils of High-Altitude Ecosystems of Sathyamangalam, India

The Sathyamangalam region, straddling the transitional zone between India's Western and
Eastern Ghats, represents a unique, high-altitude (above 4000 feet MASL) biogeographic area
critical for biodiversity. Fungi, as key drivers of decomposition, nutrient cycling, and plant health,
are integral to this ecosystem's function. This study aimed to characterize the soil fungal
communities across different habitats and elevations within this ecologically significant
landscape. Environmental DNA (eDNA) was analyzed using fungal ITS metabarcoding, sequenced
in Illumina 250 bp paired-end chemistry and the QIIME2 pipeline, with taxonomic assignments
based on the robust UNITE database. Sequencing yielded a total of 417,612 quality-filtered reads
across six samples studied, resulting in a high observed diversity ranging from 1,047 to 1,460
Operational Taxonomic Units (OTUs) per sample (Total OTUs: 7495). The communities were rich in
key functional groups, including dominant saprotrophic (Penicillium, Aspergillus and Mortierella)
and the mycorrhiza of both ectomycorrhizal and arbuscular mycorrhizal fungi. The identified
species sequences are publicly available via NCBI GenBank Accession Numbers (PQ523512-
PQ527698). Crucially, taxonomic annotation indicated the potential presence of new species
records for India, and a notable fraction of reads identified only at the Phylum level suggests
significant novel fungal diversity new to science. Many of the sequences are simply identified as
they belong to Kingdom Fungi stating their distribution as Dark Taxa. Community composition
varied significantly, reflecting differences between the distinct Western and Eastern Ghats
ecosystems. This high-resolution inventory provides a vital baseline for the high-altitude soil
mycobiota of Sathyamangalam. The observed species richness and identification of potential
novel fungal diversity underscore the ecological complexity of this transitional zone and highlight
its importance for fungal biogeography and conservation.