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Team:Valencia UPV/Project/overview
From 2014.igem.org
Project > Overview
Pests cause great economical loses in agriculture and impede an optimal use of the resources. Sexy Plant rises as a pest control strategy based on the use of mating disruption by sex pheromones. The release of sex pheromones impedes male moths to find their females, avoiding crop-damaging larvae to be born.
Sexy Plant is engineered to produce and release three moth sex pheromones which affect a broad number of Lepidoptera species (moths). We implemented previous work by Ding et al. [1] to produce the first two pheromones (Z11-16:OH and Z11-16:OAc). Inspired by Hagström et al [2], we planned the introduction of a Fatty Acid reductase to transform Z11-16:OH to Z11-16:Ald. As result, the sexy plant will be able to produce three sex pheromones involved in moth’s mating disruption (Figure 1).
Figure 1. Biosynthetic pathway of moth sex pheromones. Sex pheromones are bordered in purple . Taking Palmitic Acid CoA (16:CoA) as substrate, the expression of the genes AtrΔ11 (Desaturase) from Amyelois transitella and HarFAR (Reductase) from Helicoverpa armigera leads to the production of Z11-16:OH. By adding the gene EaDAcT (Acetyltransferase) from Euonymus alatus in the previous system, production displaced to obtaining Z11-16:OAc. If a Fatty Acid Oxidase (FAO) from Nicotiana benthamiana is included instead of EaDAcT, Z11-16:Ald will be produced.
Sexy Plant produces and releases in Nicotiana benthamiana several sex pheromones (Z11-16:OH, Z11-16:OAc and Z11-16:Ald) for a broad number of Lepidoptera species (moths). We implemented previous work on production pathways done by Ding et al. [2] into our system to produce the first two pheromones (Z11-16:OH and Z11-16:OAc). We knew about the importance of Z11-16:Aldehide to control a large number of species, so inspired by Hagström approach [3], we introduced Fatty Acid reductase to transform Z11-16:OH to Z11-16:Ald. As result, the sexy plant is able to produce three sex pheromones involved in moth’s mating disruption with 2 or 3 additional enzymes (Figure 1).
Biosafety is a major concern in our project. For that reason, we have developed a biosafety module which allows an easy identification of the plant by identity preservation and prevents the plant to spread its genetic material via pollen. Identity preservation is achieved by the production of a chromoprotein so that the plant acquires a differential colour. Dispersion of the genetic material is prevented by male sterility, as results of the tissue-specific expression of a RNAse (Barnase) in tapetum cells under the regulation of the promoter TA29 [4]. This way, autogamous Sexy Plants cannot be self-pollinate and seeds formation is blocked.
In addition, we decided that it was important to enable external control for the production of the pheromones in the Sexy Plant. Therefore we designed a genetic switch to control the activation of sex pheromone biosynthetic pathways. This genetic switch turns on the production of pheromones when a solution containing CuSO4 is sprayed on the plant. Switching ON and OFF the production produces a better use of the plant resources since nutrients can be used for normal metabolism when production is switched off.
The different genetic modules are put together to create the complete system. The complete system resembles an electric circuit, as it’s simply represented in figure 2. Our genetic circuit, once introduced in Nicotiana benthamiana creates the Sexy Plant, a plant to fight moths and avoid damages in crops.
Figure 2. Our system in an electric circuit-like format. The plant’s own metabolism is used as the energy source. The biosecurity module, composed by identity preservation and male sterility parts is always under expression in the system, to ensure the security of the transgenic plant. The pheromone synthetic pathways (A,B or C, depending on the problem pest) are activated using a genetic switch sensitive to Copper Sulfate, so system will not be producing pheromones unless it is activated with Cooper-rich solution.
REFERENCES
- Welter SC, Pickel C, Millar J, Cave F, Steenwyk RAV, et al. (2005) Pheromone mating disruption offers selective management options for key pests. California Agriculture 59: 16-22.
- Ding BJ, Hofvander P, Wang HL, Durrett TP, Stymne S, et al. (2014) A plant factory for moth pheromone production. Nat Commun 5: 3353.
- Hagström A, Wang HL, Lienard MA, Lassance JM, Johansson T, et al. (2013) A moth pheromone brewery: production of (Z)-11-hexadecenol by heterologous co-expression of two biosynthetic genes from a noctuid moth in a yeast cell factory. Microb Cell Fact 12: 125.
- Cho HJ, Kim S, Kim M, Kim BD (2001) Production of transgenic male sterile tobacco plants with the cDNA encoding a ribosome inactivating protein in Dianthus sinensis L. Mol Cells 11: 326-333.
- Sarrion-Perdigones A, Vazquez-Vilar M, Palaci J, Castelijns B, Forment J, et al. (2013) GoldenBraid 2.0: a comprehensive DNA assembly framework for plant synthetic biology. Plant Physiol 162: 1618-1631.
