Herbivore-induced ethylene suppresses a direct defense but not a putative indirect defense against an adapted herbivore.

摘要: Herbivory induces both direct and indirect defenses in plants; however, some combinations of these may not be compatible. The jasmonate signal cascade activated (nicotine accumulations) (mono- sesquiterpene emissions) whole-plant defense responses the native tobacco Nicotiana attenuata Torr. Ex Wats. Nicotine accumulations were proportional to amount leaf wounding resulting increases jasmonic acid (JA) concentrations. However, when larvae nicotine-tolerant herbivore, Manduca sexta, fed on plants or their oral secretions applied punctures, normal wound response was dramatically altered, as evidenced by large (4- 10-fold) release (i) volatile terpenoids (ii) ethylene, (iii) increased 30-fold) endogenous JA pools, but (iv) decreased unchanged nicotine accumulations. ethylene release, which insensitive inhibitors induced accumulation, sufficient account for attenuated response. Applications ethephon suppressed pre-treatment with a competitive inhibitor receptors, 1-methylcyclopropene, restored full This burst, did inhibit terpenoids. Because parasitoids are sensitive dietary intake hosts, this ethylene-mediated switching from putative represent an adaptive tailoring plant's