Insprition
Locust plague has been spreading in East Africa since the end of 2019. In February, billions of locusts spread from Africa to the Middle East, further expanding the swarm. As a result of locust swarms, a large amount of food and pasture grass were gnawed away, leading to a serious food crisis for local people. We are thus inspired to protect global food security by creating or improving an approach to locust control through the means of synthetic biology.
In the initial learning phase, we investigated several approaches to locust control, the most basic of which include physical control (capture) and chemical control (spraying). These methods more or less have disadvantages such as low efficiency and pollution of the environment. Thus, we further define the need to develop efficient and environmentally friendly means of locust control.
And what we found was that locusts do not start out as locust swarm, instead, they switch from solitary locusts to swarm locusts. According to a study published in Nature by a team of recreation researchers at the Chinese Academy of Sciences, the secret of locust swarms is that they can produce aggregation pheromones. This material can respond to the change of migratory locust population density and rise with the increase of population density. On further investigation, we learned that serotonin and guaiacol are two substances that lead to locust swarms. Therefore, we searched for enzymes that could degrade these two substances and designed a series of experiments to achieve our goals.
Background
The locust plague is a great natural disaster. There are about 500 species of locusts that cause harm to agriculture, forestry, and animal husbandry in the world. Among them, Schistocerca gregaria and Locusta migratoria are the most important agricultural pests. Once the disaster breaks out, there will be no harvest wherever they go, which will have a devastating effect on agricultural production. The scale of the locust plague that broke out in Africa in 2020 is very large, and it will be a huge blow to the agriculture of local countries such as Ethiopia, Somalia, and Kenya.
According to the United Nations Food and Agriculture Organization (FAO), the locust plague will have a greater impact on food production this year, and may eventually threaten the food security of 23 million people. The crop failure caused by the locust plague will have a more profound social impact on the African region where political turmoil and frequent violent conflicts are frequent. The security situation in parts of Africa is inherently unstable, so it cannot bear another heavy blow.
The existing chemical control methods, mainly using pesticides that are expensive, pollute the environment, and trigger drug resistance of locusts. In addition, the larger the locust swarm, the more difficult it is to be effective. For the current prevention and control of locust plagues, people need more efficient, lower pollution and lower cost solutions.
Combining the expectations of society and the important needs for the prevention and control of locust plagues, we put forward the idea, hoping to start with the formation process of locust plagues, by destroying the emergence of locust swarming behaviors, controlling the plagues before their outbreaks, and reducing the socio-economic impact of locust plagues damage.
Project overview
The locust plague is mainly caused by the gregarious type locusts; When the solitarious type locusts become the gregarious type locusts, neurotransmitter Serotonin and the intestinal pheromone Guaiacol are needed. Therefore, we proposed a design to allow bacteria to express serotonin and guaiacol decomposing enzymes in the intestines of locusts, reducing the concentration of the two substances; We also introduced a synchronized lysis circuit (SLC) for bacteria, so that enzymes be released to the intestinal lumen of locust quickly and efficiently to degrade the substrates, and ultimately disrupt the swarming behavior of locusts and avoid locust plagues. In order to ensure safety, we have also introduced a heat reponsive suicide switch, which allows bacteria to commit suicide when the summer heat is high and the locust plague is reduced, so as to avoid the problems of traditional prevention and control.
a. Verify the stability and activity of guaiacol-degrading enzymes Cytochrome P450 (CYP) , Ferredoxin reductase, and serotonin-degrading enzymes serotonin-degrading enzymes MAO and ALDR expressed in E. coli under in vitro conditions;
b. Verify the effect of synchronized lysis circuit(SLC) of E. coli
c. Combine the SLC with the guaiacol-degrading enzyme system and the serotonin-degrading enzyme system to achieve the effect of bacteria releasing functional proteins through self-lysis;
d. Develop a heat-responsive suicide switch to realize bacterial suicide under high temperature conditions (>37 ℃) and achieve the effect of a safety switch.
e. Conduct surveys and visits to farmers to obtain farmers' knowledge of locust plagues and evaluation of existing control programs;
f. Investigate and visit the Bureau of Agriculture/Ministry of Agriculture to obtain knowledge of the project background;
g. Investigate and visit the Academy of Agricultural Sciences and related scientific research units to learn about the latest locust plague prevention and control technology; and obtain opinions and suggestions from scientists on our project;
h. Conduct a questionnaire survey of the public to understand their views and feedback on biological pesticides;
References
[1]Xiaojiao，G. ,Qiaoqiao,Y., Dafang,C., Jianing, W., Pengcheng. Y., Jia. Y., Xianhui W., Le, K. 2020. 4-Vinylanisole is an aggregation pheromone in locusts, [Online].[8 October 2020].
Available from:
https://ebs.criteo.com/r/3351cfb5f47aaeb2dec0e919a9f9ec698aa98699?t=aHR0cHM6Ly93d3cubmF0dXJlLmNvbS9hcnRpY2xlcy9zNDE1ODYtMDIwLTI2MTAtNA