Piriformospora indica: The versatile and multifunctional root endophytic fungus for enhanced yield and tolerance to biotic and abiotic stress in crop plants

Abstract

In sustainable agricultural, horticultural and forestry ecosystems, different beneficial microbes are explored to enhance crop production and tolerance of plants to different (a)biotic stress conditions. The members of the order Sebacinales of Basidiomycetes form symbiotic associations with the majority of terrestrial plants. Among Sebacinales, Piriformospora indica is a unique and an interesting fungus capable of colonizing roots of many plant species and thus establishing symbiotic relationships, and also with model plants like Arabidopsis thaliana , Nicotiana tabacum (tobacco) and Hordeum vulgare (barley). The fungus lacks host specificity and is cosmopolitan in nature. Moreover, the fungus can be axenically cultivated. Positive interactions of P. indica are established for many important agricultural and horticultural plants, which allow them to grow under extreme physical and nutrient stress. The fungus promotes plant growth especially in nutrient-deficient soils, confers tolerance to abiotic (salinity, drought, water, cold, high temperature and heavy metals) and biotic (root and foliar pathogens) stress, regulates plant growth and development, induces early flowering and enhanced seed production, stimulates the production of active ingredients in medicinal plants, and helps in the hardening of micro-propagated or tissue-cultured plants. The interactions of P. indica with the model plants A. thaliana and H.vulgare are used to understand the molecular basis of these beneficial plant- microbe interactions. The current knowledge about the role of P. indica in improving the crop productivity and also in enhancing tolerance of the plant to biotic and abiotic stress is described. An attempt is also made to propose the possible mechanisms by which the fungus benefits from the crop plants.align='justify'>