Mint Reveals Its Potential For Medicines And Pesticides

Scientists from Michigan State University have traced the evolution of mint genomes for potential future applications ranging from medicines to pesticides to antimicrobials.

The The mint family of herbs, which includes sage, rosemary, basil, and even woody plants such as teak, offers an invigorating jolt to our senses of smell and taste. The new research has discovered that these plants have diversified their specialized natural characteristics through the evolution of their chemistry.

“People easily recognize members of the mint family by their specialized metabolites,” says Björn Hamberger, associate professor at the Faculty of Natural Sciences. “The metabolites are an efficient way for plants to defend themselves because they can’t run away.”

Since 2016, Hamberger has been studying specialized plant metabolites called terpenoids, which are essential for protecting plants from predators and pathogens and are also common ingredients in green and sustainable agrochemicals, antioxidants, cosmetics and fragrances.

Hamberger worked with Robin Buell, a former MSU genomics researcher now at the University of Georgia who sequenced several mint plant genomes. This collaboration with Buell’s team led Hamberger’s graduate students Abigail Bryson and Emily Lanier to discover how various genomes in the mint family have evolved and how these chemistries have emerged over the past 60 to 70 million years. .

“Over millions of years, plants have adapted and evolved for the particular niches in which they thrive, which means that these chemistries are diverse and clearly adjusted to their environment,” Hamberger explains in a statement. “So we’re trying to identify and discover pathways for these specialized metabolites that plants make.”

Using an interdisciplinary approach, Bryson identified the genomic organization of terpenoid biosynthesis and Lanier analyzed the chemical pathways. Together, Lanier and Bryson discovered something very unusual in the genome of the beauty berry, from the mint family. It has a large biosynthetic gene pool (BGC). A BGC is a group of genes located close together in the genome that participate in the same metabolic pathways. These genes are like pearls on a necklace: separate but connected. In addition, Bryson and Lanier found variants of this BGC in six other species in the mint family.

“We are learning that the physical location of genes in the genome is important,” says Bryson. “It can drive the evolution of specialized metabolic pathways in the plant, giving rise to a great diversity of interesting natural plant compounds.”

BGCs are well known in the bacterial world, but their function in plants is not fully understood. The BGC cluster of the beautyberry plant contains genes that encode two distinct terpenoid pathways. The team found that these terpenoids accumulate in various parts of the plant, such as leaves and roots, and may play different roles in adaptation.

“It’s the same base molecule, but each species makes its own version and modifies it in different ways to suit its survival needs,” Lanier explains.

Hamberger describes it as a recipe that everyone has a copy of and modifies to suit their needs and preferences.

Previous research has led to unique medicinal uses for mint plants. For example, Coleus indio can be used as a natural treatment for glaucoma and Texas sage is an effective natural antimicrobial against tuberculosis. The new molecular adaptations found by Hamberger and his team open the door to future applications of natural plant products from the mint family.

“Our team is excited about the possibilities offered by the mint family,” says Hamberger. “Those enzymes in mint, like those in the callicarpa americana plant, give us the ability to make natural plant products in the laboratory, including –hopefully in the future – good-smelling natural mosquito repellents.”

The research was published in the journal Nature Communications.