Taste detection of the non-volatile isothiocyanate moringin results in deterrence to glucosinolate-adapted insect larvae
Taste detection of the non-volatile isothiocyanate moringin results in deterrence to glucosinolate-adapted insect larvae
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DOI：
10.1016/j.phytochem.2015.08.007
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发表时间：
2015-10-01
期刊：
影响因子：
3.8
通讯作者：
Agerbirk, Niels
中科院分区：
文献类型：
--
作者：
Mueller, Caroline;van Loon, Joop;Agerbirk, Niels
异硫氰酸盐（ITC）是芸苔目植物在芥子油苷水解后释放的，因其对食草动物的负面影响而闻名，但其机制尚不清楚。 ITC 最初以溶解形式存在于草食动物摄食处，但挥发性 ITC 可能随后进入气相，并且所有 ITC 可能与基质成分发生反应。因此，在人工喂养试验中局部应用挥发性 ITC 对食草动物产生威慑可能会导致模糊的结论。在本研究中，研究了非挥发性 ITC 辣木苷（4-(α-L-吡喃鼠李糖氧基)苄基 ITC）及其硫代葡萄糖苷前体葡萄糖辣木苷对芸苔目专业昆虫食草动物的行为和味觉生理学的影响。在饲喂生物测定中，葡萄糖辣素对适应芥子油苷的菜粉蝶（鳞翅目：粉蝶科）和玫瑰花（膜翅目：Tenthredinidae）的幼虫没有威慑作用。葡萄糖辣素刺激相关的菜粉蝶（鳞翅目：粉蝶科）幼虫的摄食，并且还引起上颌外侧味觉感受器中硫代葡萄糖苷敏感的味觉神经元的电生理活动。相比之下，当局部施用于卷心菜叶盘时（直径为 1 厘米的叶盘，每个叶盘含有 12、120 或 1200 nmol 辣素），ITC 辣素对高含量的 P. napi 和 P. 甘蓝具有威慑作用，对 A. rosae 具有高水平和低水平的威慑作用。当幼虫在用辣根处理过的叶子上放置几天时，玫瑰 A. rosae 的存活率也会显着降低。此外，辣木苷还能在甘蓝菜内侧上颌味觉感受器中的威慑敏感神经元中引发电生理活动，为昆虫的威慑和第一个已知的 ITC 味觉反应提供了一种感觉机制。在模拟饲喂试验中，辣根苷的回收率很高，这与其不挥发的性质相一致。我们的结果证明了非挥发性天然 ITC 对适应芥子油苷的昆虫具有味道介导的威慑作用。 (C) 2015 Elsevier Ltd. 保留所有权利。
Isothiocyanates (ITCs), released from Brassicales plants after hydrolysis of glucosinolates, are known for their negative effects on herbivores but mechanisms have been elusive. The ITCs are initially present in dissolved form at the site of herbivore feeding, but volatile ITCs may subsequently enter the gas phase and all ITCs may react with matrix components. Deterrence to herbivores resulting from topically applied volatile ITCs in artificial feeding assays may hence lead to ambiguous conclusions. In the present study, the nonvolatile ITC moringin (4-(alpha-L-rhamnopyranosyloxy)benzyl ITC) and its glucosinolate precursor glucomoringin were examined for effects on behaviour and taste physiology of specialist insect herbivores of Brassicales. In feeding bioassays, glucomoringin was not deterrent to larvae of Pieris napi (Lepidoptera: Pieridae) and Athalia rosae (Hymenoptera: Tenthredinidae), which are adapted to glucosinolates. Glucomoringin stimulated feeding of larvae of the related Pieris brassicae (Lepidoptera: Pieridae) and also elicited electrophysiological activity from a glucosinolate-sensitive gustatory neuron in the lateral maxillary taste sensilla. In contrast, the ITC moringin was deterrent to P. napi and P. brassicae at high levels and to A. rosae at both high and low levels when topically applied to cabbage leaf discs (either 12, 120 or 1200 nmol moringin per leaf disc of 1 cm diameter). Survival of A. rosae was also significantly reduced when larvae were kept on leaves treated with moringin for several days. Furthermore, moringin elicited electrophysiological activity in a deterrent-sensitive neuron in the medial maxillary taste sensillum of P. brassicae, providing a sensory mechanism for the deterrence and the first known ITC taste response of an insect. In simulated feeding assays, recovery of moringin was high, in accordance with its non-volatile nature. Our results demonstrate taste-mediated deterrence of a non-volatile, natural ITC to glucosinolate-adapted insects. (C) 2015 Elsevier Ltd. All rights reserved.