More than 50% of the population in the world consumed rice as basic food, particularly in Asian countries. However, as a tropical cereal and also due to the changing climate, major abiotic stresses and also deficit nutrients in the soils have limited the rice production globally. These threats are not solely liable for a drastic reduction in the yield of rice but also interrupt the human beings who consume rice as a basic cereal. Usually, plants can survive against the modest level of environmental stresses. But once stresses exceed the threshold level, survival mechanisms including physio-biochemical and molecular mechanisms break down causing death of the plants and drastically reducing the final yield. It is recognized that plants follow several mechanisms to survive against stress, including stress escaping, avoidance, physio-biochemical mechanisms, and genes that confer tolerance against stress. In the case of physio-biochemical mechanisms, plants have numerous internal and external adaptation strategies including phytohormones (PH), osmoprotectants, signaling molecules, and trace elements to survive against abiotic stresses. Among these natural adaptation strategies, target PH such as gibberellins (PHGAs), cytokinins (PHCKs), auxin or indole-3-acetic acid (PHIAA), salicylic acid (PHSA), abscisic acid (PHAA), ethylene (PHET), brassinosteroids (PHBS), strigolactone (PHSL), and jasmonates (PHJAs) have a great role against environmental stresses. Since PH of plants have already proved their importance against abiotic stresses, therefore PH engineering could be a perfect platform to improve environmental stress-tolerant crops under the changing climate. This book chapter outlines the importance of PH, particularly against abiotic stresses, in plants including rice and also highlights the metabolic engineering of PH for enhancing the adaptability of rice against the harsh environment.
