ABSTRACT
Plant secondary metabolites are types of organic molecules synthesized by plants that are not directly responsible for the overall growth and development of the plant but are required for their interaction with the environment. These organic molecules are produced in response to stress. Terpenes are possibly the largest as well as the most diverse class of secondary metabolites built up from isoprene units and are simple hydrocarbons, while terpenoids are modified forms of terpenes with oxygen-containing functional groups which are biologically active. Apart from the basic medical applications, diverse classes of terpenoids are responsible for chemical interaction and protec- tion of the plant from abiotic and biotic stress conditions. Emerging tools and resources in the field of plant biotechnology have allowed researchers to study the terpenoid biosynthesis pathway and genes in order to develop strategies to control stress and build resiliency in plants. Results obtained by scientists while studying the effects of biotic and abiotic stress during terpenoid emission accumulate information regarding the sensitivity and interaction of terpenoids breaking new ground in the field of plant stress biology. In this chapter, we briefly describe the classification of terpenoids and broadly discuss their role in tolerance against various environmental 138stresses, which will come up with the significance of terpenoids as a major class of plant secondary metabolite.
