Terpene

About: Terpene is a research topic. Over the lifetime, 2208 publications have been published within this topic receiving 51480 citations. The topic is also known as: terpenes.

The organ-specific expression of terpene synthase genes contributes to the terpene hydrocarbon composition of chamomile essential oils

Abstract: The essential oil of chamomile, one of the oldest and agronomically most important medicinal plant species in Europe, has significant antiphlogistic, spasmolytic and antimicrobial activities. It is rich in chamazulene, a pharmaceutically active compound spontaneously formed during steam distillation from the sesquiterpene lactone matricine. Chamomile oil also contains sesquiterpene alcohols and hydrocarbons which are produced by the action of terpene synthases (TPS), the key enzymes in constructing terpene carbon skeletons. Here, we present the identification and characterization of five TPS enzymes contributing to terpene biosynthesis in chamomile (Matricaria recutita). Four of these enzymes were exclusively expressed in above-ground organs and produced the common terpene hydrocarbons (−)-(E)-β-caryophyllene (MrTPS1), (+)-germacrene A (MrTPS3), (E)-β-ocimene (MrTPS4) and (−)-germacrene D (MrTPS5). A fifth TPS, the multiproduct enzyme MrTPS2, was mainly expressed in roots and formed several Asteraceae-specific tricyclic sesquiterpenes with (−)-α-isocomene being the major product. The TPS transcript accumulation patterns in different organs of chamomile were consistent with the abundance of the corresponding TPS products isolated from these organs suggesting that the spatial regulation of TPS gene expression qualitatively contribute to terpene composition. The terpene synthases characterized in this study are involved in the organ-specific formation of essential oils in chamomile. While the products of MrTPS1, MrTPS2, MrTPS4 and MrTPS5 accumulate in the oils without further chemical alterations, (+)-germacrene A produced by MrTPS3 accumulates only in trace amounts, indicating that it is converted into another compound like matricine. Thus, MrTPS3, but also the other TPS genes, are good markers for further breeding of chamomile cultivars rich in pharmaceutically active essential oils.

Identification and characterization of terpene synthase genes accounting for volatile terpene emissions in flowers of Freesia x hybrida.

Abstract: The development of flower scents was a crucial event in biological evolution, providing olfactory signals by which plants can attract pollinators. In this study, bioinformatics, metabolomics, and biochemical and molecular methodologies were integrated to investigate the candidate genes involved in the biosynthesis of volatile components in two cultivars of Freesia x hybrida, Red River® and Ambiance, which release different categories of compounds. We found that terpene synthase (TPS) genes were the pivotal genes determining spatiotemporal release of volatile compounds in both cultivars. Eight FhTPS genes were isolated and six were found to be functional: FhTPS1 was a single-product enzyme catalyzing the formation of linalool, whereas the other four FhTPS proteins were multi-product enzymes, among which FhTPS4, FhTPS6, and FhTPS7 could recognize geranyl diphosphate and farnesyl diphosphate simultaneously. The FhTPS enzymatic products closely matched the volatile terpenes emitted from flowers, and significant correlations were found between release of volatile terpenes and FhTPS gene expression. Graphical models based on these results are proposed that summarize the biosynthesis of Freesia floral volatile terpenes. The characterization of FhTPS genes paves the way to decipher their roles in the speciation and fitness of Freesia, and this knowledge could also be used to introduce or enhance scent in other plants.