Recent Advances in Molecular Diagnostics of Stevia rebaudiana Bertoni: A Review

Stevia rebaudiana Bertoni, Asteraceae, is an herbaceous perennial plant native to Paraguay. Stevia is known to accumulate as high as 30% (w/w) of sweet steviol glycosides (SGs) in the leaf tissue. These glycosides are sweeter than common table sugar and are used as a non-calorific sweetener in many countries of the world. SGs have been reported to lower the postprandial blood glucose level of Type II diabetes patients and in reducing the blood pressure in mildly hypertensive patients. Due to these properties, S. rebaudiana has high socio-economic importance and biochemical and molecular research on this plant has gained pace. Based on the progressive research, this review summarizes the phytochemistry and pharmacological properties of S. rebaudiana, with special emphasis on molecular studies involving cloning of genes involved in SG biosynthesis, transgenic studies, RNAi experiments, and miRNA profiling of this plant. This will serve to learn more about the roles of miRNAs in stevia development and physiology but also to provide a framework for further designing RNAi (RNA interference) based experiments for regulation of gene expression in this species and with continued progress in genomics and database management, Stevia will soon become one of the model plants for further comparative studies.