Fungal Assemblages in the Rhizosphere and Rhizoplane of Grasses of the Subfamily Panicoideae in the Lakkavalli Region of Karnataka, India

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Fungal communities associated with roots play an important role in nutrient cycling, supporting plant growth and the biocontrol of plant diseases. Experiments were conducted in 2004-2006 to isolate and characterize, based on their morphological features, rhizosphere and rhizoplane fungi from perennial grasses of the subfamily Panicoideae growing in forests of the Western Ghats in India. Fungal species were isolated on potato dextrose, czapeck dox and water agar, in different locations and seasons. The results obtained on PDA were used for detailed analysis since most fungi occurred in high percentages. While certain grasses harbored diverse fungal species, others supported only a few species. Most fungi were isolated during winter followed by the rainy and summer seasons. The species richness, diversity and evenness of fungal assemblages in the rhizosphere and rhizoplane depended on the grass species and season. Ascomycetes were isolated in large numbers in most grass species. Species of Aspergillus, Chaetomium, Penicillium and Trichoderma occurred frequently. Certain others and non-sporulating fungi were grass species-specific. Most fungal species colonized the middle of the root more than the root tip or root base. Results suggest that perennial grasses harbor diverse fungal communities whose potential could be tapped for producing secondary metabolites and managing plant diseases.