The role of arbuscular mycorrhizal fungi (AMF) in rhizosphere soil and plant growth regulation

Mycorrhizal fungi are among the most prominent microorganisms in most natural soils. The use of biofertilizers containing arbuscular mycorrhizal fungi (AMF) and other beneficial microorganisms increases the population of microorganisms in agricultural soils and provides plant nutrients such as nitrogen, phosphorus, and potassium that improve plant growth and yield. AMF mainly forms highly branched organs (arbuscules) inside plant root cells and vesicles inside or between the host root cells. AMF is one of the most common types of mycorrhizae. Temperature, pH, CO2 concentration, moisture, light, and nutrient concentration are important factors that affect the survival and growth of mycorrhizal fungi. The main role of mycorrhizal fungi is to provide phosphorus for plant growth and to increase direct nitrogen absorption in collaboration with nitrogen-fixing microbes. So far, three methods have been used in vitro for the industrial reproduction of AMF: hydroponics, aeroponics, and simultaneous root and fungal cultivation. The last method has been the most successful in terms of economics and purity of inoculation.