Abstract
This review deals with the biological aspects of monoterpene biosynthesis with special reference to the genetic nature of chemical variations (chemotypes) and a number of genes controlling biosynthetic reaction steps leading to the terpenoid components of essential oils in Perilla frutescens. Genetic analyses revealed the existence of two dominant genes of basic importance: gene G required for the induction of the whole monoterpene biosynthesis and gene H controlling a monoterpene cyclase (limonene synthase) necessary for the formation of cyclic monoterpenes. The nature and biochemical roles of these interesting genes are discussed in detail.
