Tobacco plants advertise their defensive readiness to attacking leafhoppers
Empoasca is not a typical pest of wild tobacco. When this plant grows in its natural habitats in North America, however, it is attacked by tobacco hornworm larvae. This specialist insect is resistant to the toxic nicotine, which the plant produces as a defense against its enemies. When researchers used particular transgenic plants in field experiments, they noticed that these plants were heavily infested with Empoasca leafhoppers. In the particular transgenic plants used in this study, a certain gene had been switched off which is essential for the production of jasmonic acid. Due to their inability to produce jasmonates, the plants could not activate their defenses against herbivores, because their hormonal signalling cascades were interrupted. The result of this deficiency was visible and had been expected: a heavy infestation by tobacco hornworm larvae. The occurrence of leafhoppers, however, was a surprise, because these insects are not a part of the...