Plant Microbiome: Origin, Composition, and Functions

Microorganisms play an important role in the growth and development of a plant throughout its entire life cycle. Recent advances in the methods of molecular biological analysis have expanded our understanding of the composition and functions of plant microbiota (epiphytic, rhizosphere, and endosphere) and the molecular mechanisms associated with specific processes that govern plant-microorganism interactions. This article reviews the types of plant microbial communities, their sources of origin, and species composition, as well as the critical role they play in modulating the plant immune response against phytopathogens, improving the elemental nutrition of plants, scaring away herbivorous animals, producing phytohormones, and enabling plants to thrive under extreme environmental conditions.