Our team has proposed a new biological method for pest control, and the purpose of automatic recognition has been achieved by coupling the GPCR receptor in cotton bollworm with the GPCR pathway in yeast itself. We have spent a lot of time and energy in experimental design and component construction, which is believed to provide some help and new design ideas for IGEM teams in the future.In terms of environmental protection, we have chosen to use insect sex pheromones to interfere with mating and achieve the goal of reducing pests.In terms of AND door design, we use the dCas9 system to construct AND door. Our project is fully integrated with local conditions and needs, considering the green environment, and leveraging the concept of synthetic biology, but also expanding the scope of application.

The traditional way of pest control is generally pesticides, but now more and more advocates to use biological methods to control pests, including the use of insect pheromones to trap or interfere with mating, and also to attract natural enemies. Using the idea of synthetic biology, we want to build a device that can automatically recognize pests and release insect pheromones, by modifying Saccharomyces cerevisiae, so that it has both detection and release functions.

The detection system relies on the GPCR pathway. We coupled the GPCR receptor in cotton bollworm with the GPCR pathway of yeast itself, so that yeast has a "sense of smell" and can recognize whether tea plants are being eaten by tea aphid. The principle is detailed in design.

The release system enables yeast to attack. After recognizing that tea plants are attacked, the GPCR pathway is activated to activate the gene for synthesis of nepetol or nepetalactone, so as to achieve the purpose of interfering with mating.

After several rounds of fermentation experiments, we improved the experimental procedure and design.
The fermentation experiments of origin strain and M1 strain were carried out, and the concentrations of related products (nepetol or nepetalactone) were measured at 24h, 48h and 72h, respectively. It was found that there was no significant difference in the concentration of the three time points, so in the subsequent experiments, what’s more, most of the data measured at 24h were higher than those at the other two time points, so 24h fermentation was used as the sampling time point in the further experiments.

From M1 and M1-N1 strains‘ fermentation experiment data, we can find that although the integration of NEPS1 gene resulted in complete conversion of the nepetol, nepetalactol yield is far lower than the nepetol yield. This indicates that the NEPS1 enzyme may produce by-products in the process of catalyzing the nepetol conversation. Thus, we scanned all products of fermentation extract and tried to analyze the possible by-products based on the map, providing the basis for the further modification of enzyme.

After several rounds of fermentation experiments, we improved the experimental procedure and design.
The fermentation experiments of origin strain and M1 strain were carried out, and the concentrations of related products (nepetol or nepetalactone) were measured at 24h, 48h and 72h, respectively. It was found that there was no significant difference in the concentration of the three time points, so in the subsequent experiments, what’s more, most of the data measured at 24h were higher than those at the other two time points, so 24h fermentation was used as the sampling time point in the further experiments.

From M1 and M1-N1 strains‘ fermentation experiment data, we can find that although the integration of NEPS1 gene resulted in complete conversion of the nepetol, nepetalactol yield is far lower than the nepetol yield. This indicates that the NEPS1 enzyme may produce by-products in the process of catalyzing the nepetol conversation. Thus, we scanned all products of fermentation extract and tried to analyze the possible by-products based on the map, providing the basis for the further modification of enzyme.

Hydrophobins are secreted proteins with low molecular weights and they are about 100 amino acids long with low sequence homologies. Hydrophobins are special proteins produced by some filamentous fungi. They have both hydrophilic and hydrophobic parts, which means they are amphiphiles. Hydrophobins are able to lower the surface tension of water, and with the characteristics of amphiphiles, they can migrate to hydrophobic–hydrophilic interfaces (such as the air–water interface) . Moreover, hydrophobins can attach to some surfaces, in order to enhance the attaching ability of the engineering fungus.

We hope our engineering yeast can suspend on the surface of the liquid/gel medium in order to obtain maximum efficiency of product release. we plan to have our engineering yeast express a certain hydrophobin and assemble it on the outer surface of the yeast for the purpose of immobilising the engineering yeast on the surface of the medium,refer to design for specific principles.