This book discusses the recent advancements in the role of various biomolecules in regulating root growth and development. Rhizobiology is a dynamic sub discipline of plant science which collates investigations from various aspects like physiology, biochemistry, genetic analysis and plant–microbe interactions. The physiology and molecular mechanisms of root development have undergone significant advancements in the last couple of decades. Apart from the already known conventional phytohormones (IAA, GA, cytokinin, ethylene and ABA), certain novel biomolecules have been considered as...