Wild tomato evolution could help reduce pesticides

Michigan State University researchers have obtained a better understanding of the natural insect resistance of wild tomato plants, which could help modern plant breeders create pest-resistant tomatoes and reduce the use of pesticides.

The study looked at the evolution of a wild tomato plant found in the Atacama desert of Peru, one of the harshest environments on Earth. Researchers found a specific gene produces a sticky compound in the tips of the trichomes, or hairs, on the Solanum pennellii plant, which act as natural insect repellents that help ensure it will survive to reproduce.

"We identified a gene that exists in this wild plant, but not in cultivated tomatoes," said Rob Last, MSU Barnett Rosenberg Professor of Plant Biochemistry. "The invertase-like enzyme creates insecticidal compounds not found in the garden-variety tomato. This defensive trait could be bred into modern plants."

The researchers explained invertases regulate many aspects of growth and development in plants, and in the wild tomato the enzyme evolved to facilitate the production of new insecticidal compounds.

Unaware of their adaptive function, breeders have removed undesirable traits such as stickiness in modern cultivated tomatoes.

"We want to make our current tomatoes adapt to stress like this wild tomato, but we can only do that by understanding the traits that make them resistant," said Bryan Leong, plant biology graduate student and co-lead author. “We hope to take the defensive lessons plants already learned and apply them to existing crops."

A better understanding of the natural insect resistance of Solanum pennellii plants could enable introduction of this trait into cultivated tomatoes using traditional breeding practices.

The research was published in Science Advances.

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