Identification and regulation of the genes of the grapevine stilbene biosynthesis pathway
Project duration: 2017 to 2020
Funded by the German Research Foundation (DFG)
This project is being worked on as part of a doctoral thesis by Tobias Ziegler
Contact:
- Prof. Dr. Jochen Bogs; Room A2-161; jochen.bogs☞ Please insert an @ at this point ☜dlr.rlp☞ Please insert a period at this point ☜de
Summary
Vitis vinifera is an economically important plant that has been cultivated by mankind for thousands of years. The products of this plant, most famously wine, are not only enjoyed by humans but are also beneficial to health. This is due, in part, to a group of phenolic secondary metabolites called stilbenes. Due to their anti-oxidative, anti-inflammatory, anti-carcinogenic and anti-ageing effects, it is believed that they could potentially help prevent cardiovascular disease or be used in cancer therapy. In plants that produce stilbenes, they are active during biotic stress situations. This includes, for example, the defense against bacteria, viruses, microbes and fungi. They also help in the response to abiotic stress factors such as mechanical injury or UV radiation. Plants accumulate stilbenes in significant amounts not only in vegetative parts, but also in fruits used in the production of food, juices and wine.
Like other polyphenols, such as flavonoids or lignins, stilbenes are formed from precursors of the phenylpropanoid biosynthesis pathway. The first stilbene-specific enzyme in this process is stilbene synthase. It has been shown in various plants that there is a wide variety of stilbenes with different functions. This great diversity is achieved by chemically modifying the "basic" substance, resveratrol. These modifications include oxidation, polymerization, glycosylation or methoxylation. Previous studies have shown that the transcription factors VvMYB14 and VvMYB15 play an essential role in the regulation of the stilbene biosynthetic pathway and modification.
It has been shown that specific modified stilbenes, such as pterostilbene or viniferin, are potentially more toxic to fungi or are specifically produced in infection situations. Although it is not possible to artificially introduce modifying or regulating genes into grapevine plants due to the current views of politics and society, knowledge of this can still benefit conventional breeding. In addition, the aforementioned health-promoting effects of stilbenes make them interesting for companies in the health or cosmetics sector, where a wide range of products containing either wine plant extracts or even specifically resveratrol are already being sold today. This is now produced in yeasts(Saccharomycescerevisiae).
In order to identify the enzymes involved in the modification of stilbenes, knowledge of the two transcription factors(VvMYB14 and VvMYB15) was used to search for candidate genes in a microarray. The aim of this project is not only to show a correlation between the expression of the genes and the accumulation of the corresponding metabolites during berry ripening and in an infection, but also to demonstrate substrate and product specificity of the enzymes.