Tobacco plants are designed to produce an attractive perfume of insect sex pheromones that can be used to confuse love-seeking pests and reduce the need for harmful pesticides.
Researchers at the Earlham Research Institute in Norwich have successfully turned tobacco plants into solar-powered factories of moth sex pheromones using precision genetic engineering techniques.
Importantly, we have shown how to efficiently manage the production of these molecules so that they do not interfere with normal plant growth.
Pheromones are complex chemicals produced and released by living organisms as a means of communication. They allow them to send signals, including letting others know that members of their same species are looking for love.
Farmers can hang pheromone sprayers between crops to mimic the cues of female insects to trap males or distract them from finding a mate. Some of these molecules can be produced by chemical processes, but chemical synthesis is often expensive and produces toxic byproducts.
Leading this new research, Dr. Nicola Patron, who heads the Earlham Institute’s Synthetic Biology Group, is using cutting-edge science to get plants to produce these precious natural products.
Synthetic biology applies engineering principles to the building blocks of life: DNA. By creating genetic modules containing instructions to build new molecules, Dr. Patron and her group can turn plants such as tobacco into factories that require only sunlight and water.
“Synthetic biology allows us to manipulate plants to make more of what they already produce, or to provide genetic instructions that allow us to build new biological molecules, such as drugs or these pheromones. ‘ said Dr. Patron.
In this latest study, the team worked with scientists from Valencia’s Institute of Plant Molecular and Cellular Biology to engineer the tobacco species, Nicotiana benthamiana, to produce moth sex pheromones. The same plant was previously engineered to produce Ebola antibodies and coronavirus-like particles for use in Covid vaccines.
The group constructed a new DNA sequence in the lab to mimic the moth gene and introduced several molecular switches to precisely control its expression, effectively turning the manufacturing process on and off.
A key component of the new research was the ability to fine-tune pheromone production, as there are drawbacks to having plants build these molecules continuously.
“Increasing efficiency drains too much energy from normal growth and development,” explains Dr. Patron.
“Plants produce a lot of pheromones, but they can’t grow very big, which essentially reduces the production capacity of the production line. Our new research shows that gene expression can be more finely regulated. provide a way to do so.”
In the lab, the team set out to test and refine gene controls that produce specific mixtures of molecules that mimic the sex pheromones of moth species such as the navel orangeworm and the cotton giant salamander.
They showed that copper sulfate could be used to fine-tune gene activity, controlling both the timing and level of gene expression. This is especially important because copper sulfate is an inexpensive and readily available compound that is already approved for agricultural use.
They were even able to carefully control the production of different pheromone components, so they could fine-tune their cocktails to better suit specific moth species.
“We showed that we could control the expression levels of each gene relative to others,” said Dr. Patron. “This allows us to control the proportion of products that are manufactured.
“Moth pheromones are often a blend of two or three molecules in specific ratios, so creating the right recipe is especially important. are extracted and tested in dispensers to see how well they perform compared to female moths.”
The team hopes their research will pave the way for the daily use of plants to produce a wide range of valuable natural products.
“The main advantage of using plants is that it can be much more expensive to build complex molecules using chemical processes,” said Dr. Patron. “Plants already produce an array of useful molecules, so modern technology can be used to adapt and improve existing machinery.
“In the future, we may see greenhouses full of plant factories that offer greener, cheaper and more sustainable ways to manufacture complex molecules.”
Original: Genetically engineered plants trick pests into producing sex scents that replace pesticides
Than: Earlham Institute
