THIS book describes the most up-to-date research of the microorganisms in the area of nanoparticles, endophytes and mycorrhiza. The microbial world is the largest unexplored reservoir of biodiversity and acts as a major source for agriculture, horticulture, industrial, and medicinal applications. Bacteria and fungi the most dominant group of this diversity, which exist in different ecological niches. The growing interest in microorganisms promoting plant growth provides a fascinating biological system for the enhancement of their growth and development. Efforts have been made in this scenario for the selection of organisms and their selective genera suitable for sustainable plant growth.