Deciphering Fungal Communities in Three Species of Phlogacanthus Nees (Acanthaceae) Using Amplicon-Metagenomic...

Fungal communities play vital roles in plant health, nutrient cycling, and ecological balance. Species of Phlogacanthus Nees, valued for their medicinal and ecological importance, harbor diverse fungal microbiomes that may influence growth, resilience, and metabolite production. This study investigated fungal communities associated with three Phlogacanthus species-P. tubiflorus Nees (SKS-1), P. thyrsiformis (Roxb. ex Hardw.) Mabb. (SKS-2), and P. curviflorus (Wall.) Nees (SKS-3)-using high-throughput amplicon-metagenomic sequencing of the ITS2 region on the Illumina MiSeq platform. A total of 153 operational taxonomic units (OTUs) were identified, with SKS-2 showing the highest richness (129 OTUs), followed by SKS-1 (112) and SKS-3 (95). Seventy OTUs were shared across all species, while 10, 22, and 8 were unique to SKS-1, SKS-2, and SKS-3, respectively. Alpha diversity indices (Chao1, ACE, Shannon, Simpson, Inverse Simpson, Fisher's alpha) confirmed SKS-2 as the most species-rich fungal habitat. A high proportion of unclassified taxa in SKS-2, along with dominance of Pleosporales, suggests the presence of novel fungi with ecological and biotechnological significance. Beta diversity analysis using Bray-Curtis dissimilarity and Principal Coordinate Analysis revealed significant differences among the fungal communities of the three species. Overall, SKS-2 emerged as the most diverse habitat, while SKS-3 supported a unique but less diverse assemblage. This is the first report profiling fungal microbiomes of Phlogacanthus species. The results highlight their potential as reservoirs of endophytes with applications in plant growth promotion, stress tolerance, biocontrol, enzyme production, and bioactive metabolite discovery, offering leads for sustainable agriculture and biotechnology.