For many years, locust plague has been one of the most devastating disasters to humans and the environment, particularly in Africa, the Middle East and South Asia. In 2020, hundreds of cities were hit by the pause button as the epidemic raged. But at the same time, billions of locusts are sweeping across Africa and Asia, posing a serious threat to food security. In fact, locust plague not only took away human food, but also caused irreversible damage to the environment. Locust plagues are generally caused by migratory locusts. Its food pattern is very miscellaneous, they like to eat crops, corn, sorghum and so on. They also reproduce extremely fast, which could produce thousands of eggs per time, and their larvae can develop into adults within a month. Therefore, locusts can cause immeasurable harm to the ecological system of agriculture, forestry and animal husbandry. As the risks are pretty severe, we, the TPR_China team, hope to solve this problem through synthetic biology.
Since locust plague remained as a thorny problem, many efforts and attempts have been made. Therefore, we first investigated the existing and relatively mature methods for locust control, which are mainly divided into three categories: biological pesticides, biological locust control and chemical insecticides. However, we found that each of these approaches has its own pros and cons.
|Biological pesticides||-High selectivity, safe for people,environment and livestock- Good environmental compatibility, no pollution- Pests do not develop resistance easily||- Slow onset (usually takes one to two weeks).- The complexity of active substances results in mixed quality.- The quality shelf life of the products is low, and the requirements of production, processing, storage and transportation are high|
|Biological locust control||- Improving the local ecological environment while combating locusts- Can effectively control the number of locusts||- Takes a lot of money to increase vegetation coverage, cultivate natural enemies, and transform farmland- Works slowly and fails to solve problems in time- Can only play a preventive role, can not directly eliminate the locust swarm- Takes several decades and a lot of labor to transform the environment|
|Chemical insecticides||- High responsiveness- Destroy the locust swarm||- Easy to develop drug resistance.- Cause great harm to the environment.- Takes a lot of money to get rid of the swarms- The natural enemy tends to be killed simultaneously and thus causes locusts to flourish again- Long-term use contaminated air, water, and soil, harmful to human and animal health|
After summarizing the existing methods and searching for a lot of papers, we endeavored to find a more effective solution. At present, scientific research has confirmed that when locusts gather together, they release a variety of volatile compounds. That is, when solitary green locusts gather together, they will turn black or brown and become gregarious locusts.
So what chemicals make them "find" each other? It's actually a substance called phenylacetonitrile that's playing the trick. Thus, we came the idea that: Can we avoid locust aggregation by degrading phenylacetonitrile? When this idea came up, our team found three articles specifically and made a detailed interpretation.
At this point, we found that phenylacetonitrile does have a crucial effect on locust aggregation, and it also promotes the locusts' sexual maturation. Most interesting is that phenylacetonitrile also repels other species close by, a function that inhibits predator preference. Phenylacetonitrile, for example, makes it harder for birds to get close enough to eat the locusts. These important findings add to our confidence that controlling the spread of phenylacetonitrile could indeed be a potential means of locust control.
However, as a team dedicating to control locust plagues, we have been paying a lot of attention to various research progresses on locusts. Hence, we are informed that Doctor Le Kang's team published a new paper in Nature magazine, which established the status of 4VA as the only gathering pheromone of locusts. The importance of this study is that it has found the locust swarm pheromone that people have been looking for a long time, and it provides the possibility for future scientific intervention. The article also pointed out that unlike previous studies, PAN has a strong avoidance effect on locusts. By realizing that PAN is an avoidance pheromone, and 4VA as the only aggregation pheromone, we have adjusted our project logic: using 4VA engineered bacteria to attract locusts, and putting PAN-degrading engineered bacteria to strengthen the locusts’ aggregation. Finally, further biological measures are taken to remove the locusts within the area.
Therefore, we optimized the original project idea to produce a large amount of 4VA through synthesis and fermentation to gather locusts for subsequent elimination. PAN degrading bacteria will also be used here to help maintain the attraction ability and control partial contamination.
By realizing that PAN is an avoidance pheromone, and 4VA as the only aggregation pheromone, we have adjusted our project logic: using 4VA engineered bacteria to attract locusts, and putting PAN-degrading engineered bacteria to strengthen the locusts’ aggregation. Finally, further biological measures are taken to remove the locusts within the area.
In our mission to create a solution to eliminate the locust plague. We designed a rapidly deployable locust attraction scheme, the core of which is to synthesis specific locust aggregation pheromone 4-Vinylanisole to attract locusts and prepare for further rapid and effective eradication in the attraction area. Furthermore, an engineered bacteria which can degrade phenylacetonitrile was successfully created, avoiding its interference to the trapping effect. Through synthesis of 4-Vinylanisole and degradation of Phenylacetonitrile, locusts are “attracted” together and the site-specific control of locust swarms is realized.
And we looked for a broad-spectrum small molecule Sensor of aromatic compounds and tried to respond to PAN. To optimize the PAN degradation design of the second part of our project.
1. Construction of nitrile hydrolase engineering bacteria and verification of the degradation effect of engineering bacteria on phenylacetonitrile
2. Construct and test the response effect of the sensor to the small molecule and PAN
3. Visited farmers and other groups heavily affected by locust plague, and gathered feedback and evaluation on our existing project design
4. Investigate the public's understanding of locust plague and their preference for solutions to locust plague, and summarized our project
5. Interviewed experts in the field of locust research, investigated solutions of existing locust plague, supplemented knowledge of locust plague, and got to know the professional background of the project