Phytostimulation and Induction of Systemic Resistance by Plant Growth Promoting Fungi

In the present era, the world needs high production of crops to fulfill the demand for food. For this reason, farmers use chemicals and fertilizers to increase crop production, but this increase in yield causes damage to the environment. To prevent the harmful effects of chemicals and fertilizers, eco-friendly approaches are needed to ensure environmental and human health. For the innovative view of sustainable agriculture, biofertilizers are important replacements of chemicals for growing demands and crop production. Use of beneficial microorganisms is a new strategy to improve plant growth and crop productivity. The role of microbial populations, particularly fungi, is pivotal in solubilizing and mineralizing soil nutrients essential for plant growth. Among these microbial populations, certain fungi such as Trichoderma, Penicillium, Aspergillus, Fusarium, Phoma, or Piriformospora may act as plant growth-promoting fungi (PGPF). They showed effectiveness in significantly boosting plant growth, improving germination, seedling strength, biomass production, root hair development, photosynthetic efficiency, flowering, and overall yields. Furthermore, PGPFs exert control over foliar and root pathogens by inducing systemic resistance (ISR) in the host plants. The exceptional capabilities of some PGPFs originate from their ability to enhance nutrient absorption, stimulate the production of phytohormones and alter plant gene expression by activating signaling pathways. This chapter offers a succinct overview of the interactions between plants and their associated PGPFs, shedding light on their role in fostering enhanced plant growth and inducing systemic resistance against invading pathogens.