Team:SMS Shenzhen

Project Description

I Background

Scale insects like to be parasitic on many kinds of fruit trees, flowers, and crops. For example, succulent plants, apricot, and apple trees attract them a lot. Besides, the honeydew they secrete can cause sooty mould, therefore, it is extremely important for farmers to prevent the rampancy of scale insects. They vary in appearance, but the common thing is that they all secrete a waxy coating as their “armor”.

However, now the way people use to kill the scale insect is not great and convenient enough. The most effective method is to inject pesticide into the trunk, so when the scale insect bites the trees, they would be killed. However, using chemical way would let them start to develop a resistance to a certain kind of pesticide, and there is a huge possibility that the whole food change would be changed and the ecological balance would be destroyed. In order to bring convenience and safe to farmers, we decide to create a special bio-safe pesticide, and make the killing process faster, stronger and better.

II Introduction

Our thought of this project comes from the basic structure of the scale insect. According to other researches, the thick shell of the insect is made of three different kinds of material: a layer of wax secreted by the insect, a layer of chitin, and a layer of protein. These substances compose the harsh shell of the scale insect. Since it is a combination of wax, chitin and protein, we consider that maybe we can decompose them layer by layer, and finally destroy its shell. Without its shell, it is extremely difficult for it to stay alive, and any kind of pesticide would be able to kill that insect easily and immediately. Therefore, we put this idea forward: decompose its shell layer by layer, and finally get the result that its harsh shell is destroyed.

Our design comes from the special characteristic of the scale insect. Since its honeydew contains sucrose, we plan to use sucrose promoter, which is pretty sensitive to sucrose. After sensing the existence of sucrose, it recognizes the scale insect and starts working. Besides, since this kind of insects always damage fruit trees and succulent plants, it is important that we should keep them safe while killing those insects. Otherwise, those fruits may be stained. Thus, we design a suicide process to let bacteria suicide after wipe out those pests. After killing the insect, bacteria would kill themselves because of the suicide gene. In this way, we can ensure that our method won’t affect any plants or fruits.

III Parts Description

According to the thesis, we know that chitinase and protease are playing the most important role when the entomopathogen is trying to infect the scale insects. Entomopathogen needs chitinase to resolve the chitin layer of insects and needs protease to resolve the protein layer of insects. Base on this information, we transmit the chitinase gene and the protease gene to E. coli so that our E. coli can “open” the Chitin layer and Protein layer easily.

IV Expected Result

According to our explanation above, it is necessary to predict the result we would get from this project. As we all know, scale insect is the nightmare of many succulent plants and fruit, so probably this project would be used in agriculture and farming. We can design a pesticide kit that contains 3 kinds of engineered E.coli, which are separately designed to produce 3 kinds of enzymes. Farmers can easily mix them together at a certain portion and spread the pesticide to the scale insect. Since we don't want E.coli to have any competition with each other, those 3 kinds of E.coli should be cultivated and kept separately, and they would only be mixed just before people spray trees or crops with the final insecticide.

In order to eliminate the possibility of damage during transportation process from the lab or pesticide company to the customer, we collaborate with team SIAT-SCIE. The special technique developed by team SIAT-SCIE would keep our product safe and make it convenient enough for long-time transportation. Thanks to team SIAT-SCIE, our project becomes more reliable, controllable and applicable.