PNAS:日科学家揭示植物抵抗昆虫的一种防御机制

一项研究发现，当植物面临昆虫攻击的时候，它们释放出可在空气中传播的化学物质，这种化学物质可以被健康的临近植株接收到，并且转化为杀虫化合物，从而为正在到来的攻击做好准备。受损的植物释放出挥发性有机化合物(VOCs)，这是能够向其他植物传导信号的气味，从而让它们为即将到来的组织损伤做好准备。

Kenji Matsui及其同事研究了植物收集正在面临昆虫攻击的临近植物的挥发性有机化合物(VOCs)信号并使用这些信号加强防御的机制。这组作者把受到普通夜蛾侵扰的番茄植株放在未受侵扰的番茄植株旁边，然后分析了代谢物的制造。未受侵扰的植株在受侵扰的植株周围生长的时候所制造一种化合物——(Z)-3-hexenylvicianoside (HexVic)，其浓度高于未受侵扰的对照植株在其他未受侵扰的植株附近生长时制造的该化合物的浓度。用含有HexVic的食物培养的普通夜蛾比用正常食物培养的夜蛾的存活率和体重增加得更低，这提示了HexVic具有防御食草动物的作用。对这些被害虫侵扰的番茄植株释放出的挥发性有机化合物(VOCs)的一项分析表明，青叶醇(Z)-3-hexenol是主要的成分。

此外，暴露在空气传播的(Z)-3-hexenol中的未受侵扰的植株把这种化学物质转化成了HexVic。一项大田实验证实了在受侵扰的植株周围生长的未受侵扰的植株比在其他未受侵扰的植株周围生长的未受侵扰的植株制造了更多的HexVic。

这组作者说，这些结果证明了一种植物防御机制，即受昆虫侵扰的植株用挥发性有机化合物(VOCs)向临近的健康植株发信号，这些健康植株可能用它们制造杀昆虫的毒素。

原文摘要：

Intake and transformation to a glycoside of (Z)-3-hexenol from infested neighbors reveals a mode of plant odor reception and defense

Koichi Sugimoto, Kenji Matsui, Yoko Iijima, Yoshihiko Akakabe, Shoko Muramoto, Rika Ozawa,Masayoshi Uefune, Ryosuke Sasaki, KABIr Md. Alamgir, Shota Akitake, Tatsunori Nobuke, Ivan Galis,Koh Aoki, Daisuke Shibata and Junji Takabayashi

plants receive volatile compounds emitted by neighboring plants that are infested by herbivores, and consequently the receiver plants begin to defend against forthcoming herbivory. However, to date, how plants receive volatiles and, consequently, how they fortify their defenses, is largely unknown. In this study, we found that undamaged tomato plants exposed to volatiles emitted by conspecifics infested with common cutworms (exposed plants) became more defensive against the larvae than those exposed to volatiles from uninfested conspecifics (control plants) in a constant airflow system under laboratory conditions. Comprehensive metabolite analyses showed that only the amount of (Z)-3-hexenylvicianoside (HexVic) was higher in exposed than control plants. This compound negatively affected the performance of common cutworms when added to an artificial diet. The aglycon of HexVic, (Z)-3-hexenol, was obtained from neighboring infested plants via the air. The amount of jasmonates (JAs) was not higher in exposed plants, and HexVic biosynthesis was independent of JA signaling. The use of (Z)-3-hexenol from neighboring damaged conspecifics for HexVic biosynthesis in exposed plants was also observed in an experimental field, indicating that (Z)-3-hexenol intake occurred even under fluctuating environmental conditions. Specific use of airborne (Z)-3-hexenol to form HexVic in undamaged tomato plants reveals a previously unidentified mechanism of plant defense.

标签: 植物 昆虫 防御机制 VOCs

作者：生物帮

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