Chapter 13 - Exploration of biotechnological studies in low-calorie sweetener Stevia rebaudiana: present and future prospects

Abstract

Constant variation in climatic conditions and limitations regarding resource availability in field conditions makes plants an ideal system to be used as biofactories for constant production of variety of chemically and therapeutically important compounds. The alarming rate at which diabetes is spreading can only be estimated by WHO’s annual report which state that by the end of 2030 approximately 360 million people will be suffering from this deadly disorder. Taking the note of these recent developments there is an urgent requirement to develop a low-calorie sweetening source which can be natural, safe, and alternative to sugar and other artificial sweetening agent with an efficacious and sound economic approach. The plant Stevia rebaudiana (Bertoni) (Family Asteraceae) is a source of low-calorie sweeteners. The leaves of S. rebaudiana are main reservoir of the sweet glycosides which contain more than 30 steviol glycosides amongst which stevioside and rebaudioside A, are reported to be sweeter than sucrose. The in vitro studies in this plant are required as the regulation of the steviol biosynthesis in this plant is not well understood. The in vitro biotechnological interventions for the improvement of steviol glycoside in S. rebaudiana are targeting two aspects (1) at molecular level to understand the pathway leading to steviol glycoside biosynthesis and (2) at tissue culture level to develop new varieties with better steviol glycoside content. Combining the in vitro approaches with over expression of the targeted gene may provide improved varieties of S. rebaudiana with better steviol glycoside content.