Herbivore-induced ethylene suppresses a direct defense but not a putative indirect defense against an adapted herbivore
Herbivore-induced ethylene suppresses a direct defense but not a putative indirect defense against an adapted herbivore
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DOI：
10.1007/pl00008142
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发表时间：
2000-01-01
期刊：
影响因子：
4.3
通讯作者：
Baldwin, IT
中科院分区：
文献类型：
--
作者：
Kahl, J;Siemens, DH;Baldwin, IT
植食性诱导植物的直接和间接防御：然而，这些防御的某些组合可能不兼容。茉莉酸信号级联激活直接（尼古丁积累）和间接（单萜和倍半萜排放）在本地烟草衰减托全植物防御反应。前瓦特。尼古丁的积累量成正比的叶片受伤，从而增加茉莉酸（JA）的浓度。然而.耐尼古丁食草动物的幼虫将以植物或其口腔分泌物为食的烟草天蛾（Manducasexta）施加于叶穿刺，正常的伤口反应被显著改变，如通过（i）挥发性萜类化合物和（ii）乙烯的释放的大的（4- 10倍）增加，（iii）增加的（4- 30倍）内源JA池的积累，但（iv）减少或不变的尼古丁积累所证明的。乙烯的释放，这是不敏感的抑制剂诱导JA积累，足以占衰减尼古丁的反应。乙烯和乙烯利的应用抑制诱导尼古丁的反应和预处理的植物与乙烯受体的竞争性抑制剂，1-甲基环丙烯。完全恢复了尼古丁反应。然而，这种乙烯爆发并不抑制挥发性萜类化合物的释放。由于拟寄生蜂的曼陀罗幼虫是敏感的饮食摄入尼古丁的主机，这种乙烯介导的开关从直接到假定的间接防御可能代表一种适应性剪裁的植物的防御反应。
Herbivory induces both direct and indirect defenses in plants: however, some combinations of these defenses may not be compatible. The jasmonate signal cascade activated both direct (nicotine accumulations) and indirect (mono- and sesquiterpene emissions) whole-plant defense responses in the native tobacco Nicotiana attenuata Torr. Ex Wats. Nicotine accumulations were proportional to the amount of leaf wounding and the resulting increases in jasmonic acid (JA) concentrations. However. when larvae of the nicotine-tolerant herbivore. Manduca sexta, fed on plants or their oral secretions were applied to leaf punctures, the normal wound response was dramatically altered, as evidenced by large (4- to 10-fold) increases in the release of (i) volatile terpenoids and (ii) ethylene, (iii) increased (4- to 30-fold) accumulations of endogenous JA pools, but (iv) decreased or unchanged nicotine accumulations. The ethylene release, which was insensitive to inhibitors of induced JA accumulation, was sufficient to account for the attenuated nicotine response. Applications of ethylene and ethephon suppressed the induced nicotine response and pre-treatment of plants with a competitive inhibitor of ethylene receptors, 1-methylcyclopropene. restored the full nicotine response. This ethylene burst, however, did not inhibit the release of volatile terpenoids. Because parasitoids of Manduca larvae are sensitive to the dietary intake of nicotine by their hosts, this ethylene-mediated switching from direct to a putative indirect defense may represent an adaptive tailoring of a plant's defense response.