Molecular regulation of plant terpene biosynthesis

Terpenes are a highly diverse class of plant metabolites which vary among individuals [1], between species [2] and in response to biotic aggressors [3]. This variability may be exploited to produce specific terpenes of commercial value due to their uses in medicine, cosmetics, and food. The biochemical pathways and enzymes responsible for their synthesis have been investigated in diverse plant systems, from Arabidopsis to conifer trees, among others [4]. This knowledge forms a foundation for producing and isolating terpenes in plant-based systems, including cell cultures. The ability to regulate terpene biosynthesis at the gene expression level is crucial in this process; however, the regulatory mechanisms are poorly understood. Unlocking this knowledge holds huge potential for more precise and controlled terpene production systems.

The project aims to identify transcriptional and epigenetic regulatory mechanisms of terpene biosynthesis in plants through three research strands. First, we will analyse R2R3MYB transcription factors, based on our previous findings that over-expression variably increased the amounts and diversity of mono- and sesquiterpenes in conifers, depending on the promoter used in stable transformations [5]. Second, we will investigate epigenomic control of terpene biosynthesis. Here we may use plant hormones such as jasmonic acid to stimulate terpene accumulation, both in the short term through transcription factor activity and long-term responsiveness through chromatin modification. We will study epigenomic changes using a multi-omics approach to determine genomic regions associated with histone modifications, DNA hypomethylation, and terpene accumulation responsiveness. Thirdly, we will use knowledge from the above to engineer targeted and inducible regulation of terpene biosynthesis through transcription factor manipulation and epigenomic modifications.

The project will screen and select cell-based systems for ease of manipulation and genetic transformation, in addition to the potential to produce terpenoids of interest [see 6]. The expected results include the identification of molecular methods that allow manipulation of terpene biosynthesis in regard to their quantity, quality, or both. Ultimately this will allow the scale-up of production of terpenes of commercial interest.