Discovery of ‘Key’ Enzyme in Potato and Tomato Toxin Production

December 24, 2024

Unveiling a key mechanism of chemical defense and self-toxicity avoidance

An international research group, led by researchers from Kobe University, the Weizmann Institute of Science, the RIKEN CSRS, and Osaka University, has identified a ‘key’ enzyme involved in the biosynthesis of steroidal glycoalkaloids (SGAs)— toxic compounds in potatoes and tomatoes.

Potatoes and tomatoes produce and accumulate large amounts of toxic compounds called steroidal glycoalkaloids (SGAs) to protect themselves from insects and herbivores. At the same time, it is believed that these plants regulate the SGA production process to avoid harming themselves. However, the full picture of SGA biosynthesis remains unclear. The research group focusing on the cellulose synthase-like protein GAME15, which is implicated in SGA biosynthesis but whose exact role was previously unknown, has clarified that GAME15 functions as an enzyme evolved to transfer glucuronic acid to cholesterol, a precursor of SGAs. The study also demonstrated that disrupting GAME15 prevents SGA production, resulting in reduced insect resistance.

Furthermore, the research revealed that GAME15 forms a protein complex by linking enzymes involved in cholesterol and SGA biosynthesis. This protein assembly promotes efficient reactions and minimizes the accumulation of harmful metabolic intermediates, suggesting that GAME15 plays a "key" role in enabling plants to produce SGAs efficiently while avoiding self-toxicity.

Original article

Science doi: 10.1126/science.adq5721

A. Jozwiak, S. Panda, R. Akiyama, A. Yoneda, N. Umemoto, K. Saito, S. Yasumoto, T. Muranaka, S. A. Gharat, Y. Kazachkova, Y. Dong, S. Arava, I. Goliand, R. Nevo, I. Rogachev, S. Meir, M. Mizutani, A. Aharoni,

"A Cellulose Synthase-like Protein Governs the Biosynthesis of Solanum Alkaloids".

Contact

Naoyuki Umemoto
Senior Scientist
Metabolomics Research Group