Wild tomato plant key to reduce pesticide use

The team recently identified an evolutionary function in wild tomato plants that could be used by modern plant breeders to create pest-resistant tomatoes.

Natural insect repellants

The study, published in Science Advances, traced the evolution of a specific gene that produces a sticky compound in the tips of the trichomes, or hairs, on the Solanum pennellii plant found in the Atacama desert of Peru – one of the harshest environments on earth. These sticky hairs act as natural insect repellants to protect the plant, helping ensure it will survive to reproduce.

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Dan Lybrand and Bryan Leong, MSU graduate students and study co-authors, examine glandular trichomes on the Solanaceae plant’s leaf surface. – Photo: Michigan State University

“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.”

Breeders removed undesirable traits

According to Last modern cultivated tomatoes make fewer of the compounds found in wild plants because – unaware of their adaptive function -breeders removed undesirable traits such as stickiness.

Using techniques such as the CRISPR gene-editing technology, the team identified an invertase-like enzyme specific to the cells at the tips of the sticky hairs. Invertases regulate many aspects of growth and development in plants. In the wild tomato, the enzyme evolved to facilitate the production of new insecticidal compounds.

This discovery is a step toward understanding the natural insect resistance of Solanum pennellii plants, which could enable introduction of this trait into cultivated tomatoes using traditional breeding practices.