ABSTRACT
This chapter discusses on the concept and practices of inoculation because it is more connected to the functioning of microbiomes than is the broader category of biofertilization. Generally, inoculation introduces its active, biological components to or through plant roots. Fertilization in general refers to adding inorganic materials to the soil, usually some form of nitrogen or a phosphate such as zinc phosphate. The distinction between the two terms is somewhat hazy. The host and its associated microorganisms function in many ways as a unit which is referred to as a holobiont now that the myriad relationships among plants, microbes, and their soil environment are becoming better understood. The modifications in plant gene expression associated with the introduced microbes include changes in mRNA that regulate production of phytohormones, photosynthesis efficiency, carbohydrate metabolism, and cell division and expansion. The myriad connections within a holobiont are becoming more decipherable at the molecular level with state-of-the-art analytical methods.
