Lavandula angustifolia Mill. a model of aromatic and medicinal plant to study volatile organic compounds synthesis, evolution and ecological functions

Lavandula angustifolia Mill. or true lavender is an emblematic plant from dry and calcareous hills of the south of France. Lavender essential oils obtained from inflorescences harvested at bloom stage are mainly composed of monoterpenes and few sesquiterpenes. The characteristic lavender smell is due to linalool and linalyl acetate that represent more than half of the emitted volatile organic compound (VOC) quantity. These monoterpenoids are derived from plastidial pathway precursors. The regulation of this pathway in lavender is mainly managed by the successive expression of two DXS during flower development. In the light of 10 years of published data on lavender, it appears that biochemical pathways of main terpenes are mostly depicted. Several transcriptomic libraries are available and a genome at chromosome scale has been assembled and molecular markers developed. The diversity of lavender terpenes and their biosynthesis are reviewed with additional original data regarding the anatomical glandular structures and expression of genes involved in IPP biosynthesis.