Tomato Defense Weapons

Whiteflies, spider mites, and aphids are among the insects that prey on tomatoes bound for grocery store shelves, devouring the fruit and also spreading viruses that can destroy entire shipments in the $53 billion industry. Researchers in the Netherlands and Germany have now taken a biosynthetic pathway for herbivore-deterring terpenes found in wild tomato varietals and reintroduced the genes into commercial tomato plants via genetic engineering and traditional breeding (Proc. Natl. Acad. Sci. USA., DOI: 10.1073/pnas.1208756109). The plants produce 7-epizingiberene in their stems and leaves but not in their fruit, so tomato flavor should not be altered, says Robert C. Schuurink, a plant biochemist at the University of Amsterdam who led the research. To reintroduce the defensive sesquiterpene into cultivated tomatoes, the team needed to first identify which genes were involved in 7-epizingiberene biosynthesis. A stereoisomer of 7-epizingiberene, α-zingiberene, is found in basil, turmeric, and cardamom plants but does not repel tomato plant herbivores.