Key Laboratory of Aquatic Plant and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Institute of Plant Sciences, University of Bern, Bern, Switzerland.
Plant Cell Environ. 2019 Jun;42(6):1964-1973. doi: 10.1111/pce.13534. Epub 2019 Apr 8.
Volatile organic compounds (VOCs) emitted by plant roots can influence the germination and growth of neighbouring plants. However, little is known about the effects of root VOCs on plant-herbivore interactions of neighbouring plants. The spotted knapweed (Centaurea stoebe) constitutively releases high amounts of sesquiterpenes into the rhizosphere. Here, we examine the impact of C. stoebe root VOCs on the primary and secondary metabolites of sympatric Taraxacum officinale plants and the resulting plant-mediated effects on a generalist root herbivore, the white grub Melolontha melolontha. We show that exposure of T. officinale to C.stoebe root VOCs does not affect the accumulation of defensive secondary metabolites but modulates carbohydrate and total protein levels in T. officinale roots. Furthermore, VOC exposure increases M. melolontha growth on T. officinale plants. Exposure of T. officinale to a major C. stoebe root VOC, the sesquiterpene (E)-β-caryophyllene, partially mimics the effect of the full root VOC blend on M. melolontha growth. Thus, releasing root VOCs can modify plant-herbivore interactions of neighbouring plants. The release of VOCs to increase the susceptibility of other plants may be a form of plant offense.
植物根系排放的挥发性有机化合物（VOCs）会影响邻近植物的发芽和生长。然而，对于根系 VOCs 如何影响邻近植物的植物-草食动物相互作用，我们知之甚少。多裂臂形草（Centaurea stoebe）会向根际持续释放大量倍半萜烯。在这里，我们研究了 C. stoebe 根系 VOCs 对同域蒲公英（Taraxacum officinale）植物的初生和次生代谢物的影响，以及这些 VOCs 对一种普通根食草动物——白纹夜蛾幼虫（Melolontha melolontha）的植物介导作用。结果表明，暴露于 C.stoebe 根系 VOCs 不会影响防御性次生代谢物的积累，但会调节蒲公英根系中的碳水化合物和总蛋白水平。此外，VOC 暴露会增加 M. melolontha 在蒲公英植株上的生长。暴露于 T. officinale 的 C. stoebe 根系的一种主要 VOC——（E）-β-石竹烯，部分模拟了根系 VOC 混合物对 M. melolontha 生长的影响。因此，释放根系 VOC 可以改变邻近植物的植物-草食动物相互作用。向环境中释放 VOC 以增加其他植物的易感性可能是植物防御的一种形式。
