Team:CIDEB-UANL Mexico/Project-Idea

Problem - Our Model - Important Aspects
Problem - Return
Agriculture is a very important part of human life, because from this activity the majority of our foods are developed, thus our alimentation depends on it greatly; in this practice, many factors may affect crop growth, as are insects, and they can also directly affect the final products. An effective and popular answer for this problem is the use of pesticides, but there are known negative consequences for their use in crop grounds. Potato crops are the area we are interested to work with, having investigated the plague that affects it, the white worm. This worm is known to affect the roots of the plant and can even destroy it. We want to eliminate this problem in secure conditions with a system that can destroy the plague without causing harm to the crop and only affects the insect.

Image retrieved from: http://www.potato2008.org/images/stages.gif

Our model - Return
In our system, we are aiming to avoid this problem with a pesticide that is to be produced in specific temperature conditions. It is going to be a modified bacterium, in this case we will be working with E. coli, that it is going to be releasing the pesticide (Vip3Ca3) regulated by temperature related to the optimum temperature in which the worm develops and grows. We constructed a model of the circuit that would be finally inserted in the bacteria. In order to do so we divided it in two genes:

The first gene consists of a regulable promoter repressed by the cI lambda (parts registry name: R0051), linked to a rbs and followed by the Vip3ca3, this part currently does not exist in the parts registry page, so we are planning on inserting it as a new part, by converting it into a BioBrick with standard cutting sites. That’s why it was requested to be synthesized, to have a more practical use. After the rbs we will manually assemble a reporter to notice that the production of the Vip3Ca3 is actually occurring. In this case we will use GFP as a reporter with degradation tag LVA in order to see if the Vip3Ca3 production is actually occurring (later we are going to explain a little more about the degradation tag.

The second part has of a constitutive promoter and a riboswitch that will regulate, by temperature, the Vip3ca3 production. After the riboswitch the gene that will be expressed is the Vip3Ca3, then a RBS in order to add a repressor after this. It was decided to synthesize these parts for the assembly because it was more practical. After the synthesized parts, we are going to assembly manually adding the repressor lamba cI (In the parts registry is located as the C0051).

Important Aspects - Return
Two important aspects of our circuit are the riboswitch and the Vip3Ca3 protein.
Riboswtich: this works as a RBS but it activates transcription at temperatures higher than 20ºC having its optimum state at 37ºC. As we needed the inverse of this function as well, we used a set of promoter repressor to stop the production at 20ºC.
Vip3Ca3: being a new protein, as not found in parts registry we asked for it to be synthesized (for more information about this protein you can see an article in the safety section).

To spread our bacteria in the field, we have a made a robot, specially developed for this task, to have a more efficient the work. This has the purpose to take advantage of ground conditions for an optimum spread of bacteria (more information abot the robot is available in the software section).

Our goal is to have and give an alternative way to combat and/or eliminate plague problems, in this particular case, we are working on the white worm found in potato crops in a secure way which controls the system regulating the production. This, with the objective of avoiding several things: - Overproduction
- As the Vip3Ca3 can be broken down after a certain amount of time there is no problem with bioaccumulation.
- Contamination, Vip3Ca3 does not harm the environment.
- Unnecessary production; this system is regulated by temperature because it was better this way against the white worms life cycle but it can be regulated by different intervals of temperature (with different riboswitch). We can also inverse the activation of the system by using only the part with the Vip3Ca3 without the promoter-reppresor set.

One of the purposes of our work is to function as a model, in which the riboswitch and the toxin can be exchanged for other that works for different plagues, this including other kinds of pesticides that aim to affect other insects, or ven change reporters instead of GFP.