Natural Products of the Rhizosphere and Its Microorganisms Bioactivities and Implications of Occurrence

This chapter summarizes the distribution, structural diversity, biological activity, and implications of the occurrence of natural products of the rhizosphere, which are derived from its associated plants and microorganisms. Also discussed is the importance of these and small-molecule rhizodeposition products in a variety of interactions between the rhizosphere organisms. The rhizosphere plays host to rich and diverse communities of bacteria and fungi. The term microbial diversity can be described as the propensity of microorganisms from different taxa, as well as their distribution within the taxa, including the diversity of fungi and bacteria, in microbial communities of a given ecosystem. Comparative studies of bacterial diversity in the rhizosphere and bulk soils involving cultivation-based analysis have revealed a higher population of these microorganisms in the rhizosphere. The rhizosphere is known to host a great diversity of fungal species, and this is strongly influenced by the plant species, its developmental stage, and the soil type.