Team:GDSYZX/Description

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Project Description

Background

At present ,many people suffer from cancer and cardiovascular diseases. However, these diseases have high death rate. We high school students wanted to do something to reduce the death rate. While most scientists were busy creating western medicines to cure these diseases，we tried to use traditional Chinese medicine to achieve our goal . We found that a kind of Chinese medicine called Rhodiola rosea was effecting to either cancer or cardiovascular diseases. Unfortunately，this plant usually grows on the snow mountains, which means it is both rare and difficult to get.

But the present methods to obtain salidroside are extraction from wild or cultivatedplants and chemical synthesis. Not only a complex extraction process is required in those methods, but also they have a very low extraction rate. A huge amount of wasted Rhodiola makes it an government-rated Class I endangered Tibetan medicinal material.

Salidroside is the main active ingredient in R.rosea So our project aims to use the techniques of synthetic biology to provide a sustainable and efficient way to obtain salidroside in Arabidopsis thaliana's protoplasts in order to solve the problems encountered in salidroside production. We use

plant cell engineering in combination with synthetic biology,

which is one of the highlights of our project.

The Synthesis Pathway of Salidroside

By consulting the relevant references, we know the metabolic pathway of salidroside in Rhodiola. It has been reported that L-tyrosine can produce 4 hydroxyphenylacetaldehyde directly ;4 hydroxyphenylacetaldehyde catalyzed by 4HPAAS(1473 bp) and be reduced to tyrosol;tyrosol under the catalysis of 4HPAR, then glycosylation can be carried out under the action of protein with T8GT activity to form salidroside. Compared with other proteins with T8GT activity, UGT33 (1497 bp)has the highest catalytic efficiency for tyrosol to salidroside. In addition, the study showed that salidroside. could be detected in tobacco leaves only by hetero-expression of 4HPAAS and RrUGT33. This proved that 4HPAAS and RrUGT33 were the two key genes we needed to find.

Our Approach

The protoplasts of Arabidopsis thaliana have the characteristics of convenient material acquisition, short culture cycle and high transformation efficiency, which are especially suitable for the expression of foreign genes and the detection of their expressed products. What's more, the protoplast of Arabidopsis thaliana has a mature protoplast transformation system. At present, it has not been reported whether the foreign genes expressing Rhodiola Sachalinensis can detect the product salidroside. Therefore, we intend to use the hetero-expression of 4HPAAS and RrUGT33 in the protoplast system of Arabidopsis thaliana to explore the synthesis pathway of salidroside. It lays a foundation for further study of the synthesis pathway of salidroside, and also provides a theoretical basis for the realization of industrial production of salidroside.