ABSTRACT
This chapter discusses the interactions of microorganisms with their surrounding biota in soil with an emphasis on prokaryotes. It describes the interactions among bacteria, as well as between bacteria and higher organisms such as fungi, protozoa, Bdellovibrio, and plant roots. In soil, the biofilms/microcolonies are mostly attached to solid surfaces, such as specific soil particles, soil organic matter domains, plant roots, and decaying organisms. Microbial function is the key determinant of the dynamics within a microbial community that is forming a microbial assemblage. During biofilm development, differential gene expression occurs in the microbial cells that grow in the biofilm. The chapter examines examples of the aforementioned interactions as paradigms for the varied ways soil microorganisms interact with their physically proximal neighbor organisms. Microorganisms in soil can respond to their surroundings by sensing local conditions of water content, pH, temperature, and the level of chemical compounds including nutrients.
