Molecular mechanism underlying Piriformospora indica-mediated plant improvement/protection for sustainable agriculture.

The beneficial endophytic microorganisms have received significant attention in agriculture because of their exceptional capabilities to facilitate functions like nutrient enrichment, water status, and stress tolerance (biotic and abiotic). This review signifies the molecular mechanisms to better understand the Piriformospora indica-mediated plants improvement or protection for sustainable agriculture. P. indica, an endophytic fungus, belonging to the order Sebacinales (Basidiomycota), is versatile in building mutualistic associations with a variety of plants including pteridophytes, bryophytes, gymnosperms, and angiosperms. P. indica has enormous potential to manipulate the hormonal pathway such as the production of indole-3-acetic acid which in turn increases root proliferation and subsequently improves plant nutrient acquisition. P. indica also enhances components of the antioxidant system and expression of stress-related genes which induce plant stress tolerance under adverse environmental conditions. P. indica has tremendous potential for crop improvement because of its multi-dimensional functions such as plant growth promotion, immunomodulatory effect, biofertilizer, obviates biotic (pathogens) and abiotic (metal toxicity, water stress, soil structure, salt, and pH) stresses, phytoremediator, and bio-herbicide. Considering the above points, herein, we reviewed the physiological and molecular mechanisms underlying P. indica-mediated plants improvement or protection under diverse agricultural environment. The first part of the review focuses on the symbiotic association of P. indica with special reference to biotic and abiotic stress tolerance and host plant root colonization mechanisms, respectively. Emphasis is given to the expression level of essential genes involved in the processes that induce changes at the cellular level. The last half emphasizes critical aspects related to the seed germination, plant yield, and nutrients acquisition.