Chapter 15 - Microbiome in Crops: Diversity, Distribution, and Potential Role in Crop Improvement

Abstract

The use of plant growth-promoting microbes may prove useful in developing strategies to facilitate growth of different crops. The use of microbe formulation with the aim of improving nutrient availability for plants is an important practice and necessary for agriculture. During the past couple of decades, the use of microbial inoculants for sustainable agriculture has increased tremendously in various parts of the world. Significant increases in growth and yield of important cereal crops in response to inoculation with PGP microbe have been repeatedly reported. The actual biodiversity of PGP microbes will be illustrated by examples of genera and species chosen from the literature and their mechanisms of action for the following different domain archaea, bacteria, and fungi of different phylum/groups, for example, Actinobacteria, Ascomycota, Bacteroidetes, Basidiomycota, Crenarchaeota, Euryarchaeota, Firmicutes, and Proteobacteria (α/β/γ/δ). Among these groups, Bacillus and Bacillus-derived genera (BBDG) and γ-Proteobacteria have been characterized and formulated for growth and yield of different crops. These microbes are naturally occurring that aggressively colonize plant roots and benefit plants by providing growth promotion. PGP microbes are reported to influence the growth, yield, and nutrient uptake by different mechanisms of solubilization of phosphorus (P), potassium (K), and zinc (Zn) and biological N2 fixation and production of indoleacetic acid, gibberellic acid, siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. The diversity of microbes associated with crops and their beneficial role in crop improvement is reviewed and discussed.