Pheromones are intricate chemical compounds that organisms produce and emit as a form of communication. They enable members of the same species to transmit messages, including signaling their search for a mate.

To mimic the signals of female insects, farmers can place pheromone dispersers among their crops, which either trap or distract male insects from finding a mate.

While some of these molecules can be produced by chemical methods, chemical synthesis often generates harmful byproducts and incurs high expenses.

Researchers at the Earlham Institute in Norwich have used precision gene engineering techniques to transform tobacco plants into solar-powered factories that produce moth sex pheromones.

The key feature is that the scientists have demonstrated how these molecules can be produced without hindering the normal growth of the plant.

The Synthetic Biology Group, headed by Dr Nicola Patron at the Earlham Institute, employs advanced techniques to enable plants to produce highly valuable natural products. Through the principles of synthetic biology, the team constructs genetic modules that provide instructions to produce new molecules, which ultimately transforms plants such as tobacco into highly efficient factories. These plants merely require access to sunlight and water to carry out the production process.

Synthetic biology, as explained by Dr. Tatron, can allow us to engineer plants to make a lot more of something they already produced, or we can provide the genetic instructions that allow them to build new biological molecules, such as medicines or these pheromones.

The research team collaborated with scientists at the Plant Molecular and Cell Biology Institute in Valencia to genetically engineer Nicotiana benthamiana, a species of tobacco, to produce moth sex pheromones. This plant has previously been modified to produce Ebola antibodies and even coronavirus-like particles for use in COVID-19 vaccines. The group created new DNA sequences in the laboratory to imitate the genes of moths and added a few molecular switches to regulate their expression precisely, turning the manufacturing process on and off as needed.

A crucial aspect of the recent study was the capacity to adjust the production of pheromones, as forcing plants to constantly produce these molecules can have negative consequences.

As we increase the efficiency, too much energy is diverted away from normal growth and development, adds Dr. Patron.

The plants are producing a lot of pheromone but theyre not able to grow very large, which essentially reduces the capacity of our production line.

This new study provides a way to regulate gene expression with much more subtlety.

The team conducted experiments in the laboratory to test and improve the regulation of genes responsible for generating a mixture of particular molecules that imitate the sexual pheromones of moth species, such as cotton bollworm and navel orangeworm moths.

Through their research, they demonstrated that copper sulfate could be utilized to precisely adjust the behavior of these genes, enabling them to manage both the extent and timing of gene expression.

This is especially significant since copper sulfate is a cost-effective and easily accessible substance that has already been approved for agricultural use. Moreover, they were able to meticulously regulate the production of diverse pheromone components, which enabled them to modify the combination to better match specific moth species.

Weve shown we can control the levels of expression of each gene relative to the others, points out Dr. Patron. This allows us to control the ratio of products that are made.

Getting that recipe right is particularly important for moth pheromones as theyre often a blend of two or three molecules in specific ratios. Our collaborators in Spain are now extracting the plant-made pheromones and testing them in dispensers to see how well they compare to female moths.

The team aims to establish a pathway for using plants as a standard method for producing an extensive variety of valuable natural products.

A major advantage of using plants is that it can be far more expensive to build complex molecules using chemical processes, adds Dr. Patron. Plants produce an array of useful molecules already so were able to use the latest techniques to adapt and refine the existing machinery.

In the future, we may see greenhouses full of plant factories providing a greener, cheaper and more sustainable way to manufacture complex molecules.

The findings were published in the journalPlant Biotechnology.

Image Credit: Getty

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