New study explores source of flavour additives

Just one cellular pathway produces the raw ingredients plants use to make thousands of compounds, find US researchers at Purdue University and the Max Planck Institute for Chemical Ecology.

"Our research has applications in the future metabolic engineering of essential oil production,"​ said Natalia Dudareva, professor of horticulture and lead researcher of the study.

The yield of these compounds depends on the amount of materials available in the cell, and knowing where these compounds come from and which pathway produces them is the place to start, she explains.

Dudareva and her colleagues report in the January 18 issue of Proceedings of the National Academy of Science​ that the molecular precursors to a group of compounds called terpenoids - the largest and most diverse family of natural products - come from a single plant pathway, located inside the same part of a cell where photosynthesis occurs.

Terpenoids are made from compounds called precursor molecules, which are a kind of molecular raw material. The scientists report that identical precursor molecules can transform into unique compounds by following different molecular pathways.

Scientists previously discovered that two independent pathways, located in different compartments within a plant cell, use these precursor molecules to produce terpenoids. Most scientists assumed that both pathways were capable of producing these precursor molecules as well.

The discovery that only one pathway produces these precursors is a significant breakthrough, said Dudareva​, who used snapdragon flowers in this research

"This is the first time anyone has realised that only one of the two available pathways operates to make the precursor,"​ she added.

Dudareva also found that while some of the precursor molecules remain in the compartment where they are made, some travel through the cell to another compartment, where they enter a second pathway in terpenoid production.

"This work hints at the existence of a transporter to carry precursor molecules across the cell. We need to figure out how compartments facilitate this one-way flow of precursor molecule,"​ said David Rhodes, Purdue professor of horticulture and a collaborator on the paper.