Importance of Soil Microbes in Improving Citrus Production

Soil is a major inhabitant of a vast range of microbial species. Soil microbes play crucial roles in various soil biochemical activities like nutrient cycling, and improving soil fertility and productivity. Fruit plants like citrus are widely dependent on soil for their optimum growth and productivity due to their short root hairs. For satisfying the plant demand for water and nutrients, citrus plants require root mycorrhizal (AM) colonization. Various studies have highlighted the role of AM fungi in stimulating the growth and productivity of citrus. AM species differ in their response to citrus varieties’ nutrient uptake, especially phosphorous, copper, and zinc (less mobile nutrients). Mycorrhizal response varies among different citrus rootstock, moisture availability, and soil conditions. The application of AM as a bioinoculant is perceived to increase plant vigor and fruit quality under abiotic and biotic stress conditions. It increases plant tolerance and immunity against various stresses by increasing mineral absorption, protecting the root, and modulating the enzymatic response. In this chapter, we describe the importance of soil microbes especially mycorrhizal fungi in promoting the growth of various citrus species. In addition, we also discussed the factors which play their role in stimulating citrus growth by mycorrhizal fungi. Mycorrhizal fungi play a crucial role in citrus growth as it increases nutrient absorption, secrete glomalin-related soil protein (GRSP), improve soil health, explore root influential zone, protect plants from soil-borne pathogens, and increase plant resistance against various biotic and abiotic factors.