Department of Biochemistry, Max Planck Institute for Chemical Ecology, 07745, Jena, Germany.
Research Group Biosynthesis/NMR, Max Planck Institute for Chemical Ecology, 07745, Jena, Germany.
Plant Cell Environ. 2019 Dec;42(12):3293-3307. doi: 10.1111/pce.13628. Epub 2019 Aug 27.
Belowground (BG) herbivory can influence aboveground (AG) herbivore performance and food preference via changes in plant chemistry. Most evidence for this phenomenon derives from studies in herbaceous plants but studies in woody plants are scarce. Here we investigated whether and how BG herbivory on black poplar (Populus nigra) trees by Melolontha melolontha larvae influences the feeding preference of Lymantria dispar (gypsy moth) caterpillars. In a food choice assay, caterpillars preferred to feed on leaves from trees that had experienced attack by BG herbivores. Therefore, we investigated the effect of BG herbivory on the phytochemical composition of P. nigra trees alone and in combination with AG feeding by L. dispar caterpillars. BG herbivory did not increase systemic AG tree defences like volatile organic compounds, protease inhibitors and salicinoids. Jasmonates and salicylic acid were also not induced by BG herbivory in leaves but abscisic acid concentrations drastically increased together with proline and few other amino acids. Leaf coating experiments with amino acids suggest that proline might be responsible for the caterpillar feeding preference via presumptive phagostimulatory properties. This study shows that BG herbivory in poplar can modify the feeding preference of AG herbivores via phytochemical changes as a consequence of root-to-shoot signaling.
地下（BG）食草动物可以通过改变植物化学物质来影响地上（AG）食草动物的表现和食物偏好。大多数关于这种现象的证据都来自于草本植物的研究，但木本植物的研究却很少。在这里，我们研究了黑杨（Populus nigra）树上的 BG 食草动物——欧洲鳃金龟幼虫（Melolontha melolontha）对 AG 食草动物——舞毒蛾幼虫（Lymantria dispar）的取食偏好是否以及如何产生影响。在食物选择试验中，毛毛虫更喜欢取食 BG 食草动物攻击过的树木的叶子。因此，我们单独研究了 BG 食草对 P. nigra 树木的植物化学成分的影响，以及与 L. dispar 毛毛虫的 AG 取食相结合的影响。BG 食草不会增加挥发性有机化合物、蛋白酶抑制剂和柳醇类等系统 AG 树木防御物质。茉莉酸和水杨酸也不会因 BG 食草而在叶片中诱导产生，但脱落酸的浓度与脯氨酸和其他几种氨基酸一起急剧增加。用氨基酸进行叶片涂层实验表明，脯氨酸可能通过假定的取食刺激特性对毛毛虫的取食偏好负责。本研究表明，杨树的 BG 食草可以通过根到茎的信号传递导致植物化学成分的变化，从而改变 AG 食草动物的取食偏好。
