Piriformospora indica: A Novel Plant-growth-promoting Root Endophyte Fungus for Climate-resilient and Sustainable Agriculture

Abstract

Piriformospora indica (reclassified as Serendipita indica) is an axenically culturable, root-colonizing endophytic fungus of the order Sebacinales, originally isolated from the rhizosphere of woody shrubs in the Thar Desert, India. Unlike obligate arbuscular mycorrhizal fungi, P. indica completes its life cycle on synthetic media without a living host, which makes it uniquely amenable to mass multiplication and formulation ("Rootonic") as a commercial bioinoculant. Since its discovery, an extensive body of literature has documented its unusually broad host range and its capacity to enhance seed germination, root and shoot biomass, nutrient acquisition, and crop yield across cereals, pulses, oilseeds, vegetables, fruit crops and ornamentals. Mechanistically, the fungus colonizes the root cortex through a biotrophic phase followed by a controlled, cell-death-associated phase, during which it reprograms host hormonal networks (auxin, gibberellin, jasmonic acid), strengthens enzymatic and non-enzymatic antioxidant defences and enhances osmolyte accumulation, thereby conferring tolerance to drought, salinity, heat, heavy-metal, and mechanical-impedance stresses. In parallel, P. indica directly and indirectly modifies the physical, chemical, and biological properties of the rhizosphere, improving nutrient mineralization, enzyme activity and soil aggregation, while also showing promise in the phytoremediation of cadmium, lead, copper and petroleum-hydrocarbon-contaminated soils. This review covers the taxonomy and morphology of P. indica, its mass-multiplication and field-application protocol, its mechanisms of plant growth promotion and abiotic-stress tolerance, and its effects on yield and soil health. The evidence positions P. indica as a dual-benefit, climate-resilient bioagent with strong potential for integration into sustainable and precision agricultural systems.