Max Planck Institute for Chemical Ecology, Department of Entomology, 07745 Jena, Germany.
New Phytol. 2011 Jan;189(2):549-56. doi: 10.1111/j.1469-8137.2010.03486.x. Epub 2010 Oct 1.
Glucosinolates are plant secondary metabolites used in host plant recognition by insects specialized on Brassicaceae, such as the diamondback moth (DBM), Plutella xylostella. Their perception as oviposition cues by females would seem to require their occurrence on the leaf surface, yet previous studies have reached opposite conclusions about whether glucosinolates are actually present on the surface of crucifer leaves. DBM oviposits extensively on Barbarea vulgaris, despite its larvae not being able to survive on this plant because of its content of feeding-deterrent saponins. Glucosinolates and saponins in plant tissue and mechanically removed surface waxes from leaves of Barbarea spp. were analyzed with high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Surface waxes from leaves of Barbarea spp. contained glucosinolates, but not feeding-deterrent saponins. Our research is the first to show that glucosinolates are present on the leaf surface of Barbarea spp., but not in other crucifers investigated, resolving some conflicting results from previous studies. Our research is also the first to quantify glucosinolates on the leaf surface of a crucifer, and to show that the concentrations of glucosinolates found on the leaf surface of Barbarea spp. are sufficient to be perceived by ovipositing DBM.
硫代葡萄糖苷是植物次生代谢物，被专门以十字花科为食的昆虫（如小菜蛾）用于寄主植物识别。雌性昆虫将其作为产卵线索的感知似乎需要它们出现在叶片表面，但之前的研究对于硫代葡萄糖苷实际上是否存在于十字花科叶片表面得出了相反的结论。尽管小菜蛾幼虫因含有拒食皂角苷而无法在其叶片上存活，但它仍大量产卵于菥蓂属植物上。利用高效液相色谱（HPLC）和液相色谱-质谱（LC-MS）分析了菥蓂属植物组织中的硫代葡萄糖苷和皂角苷以及从叶片上机械去除的表面蜡。菥蓂属植物叶片的表面蜡中含有硫代葡萄糖苷，但不含拒食皂角苷。我们的研究首次表明，硫代葡萄糖苷存在于菥蓂属植物的叶片表面，但在其他研究的十字花科植物中不存在，解决了之前一些相互矛盾的研究结果。我们的研究还首次对十字花科植物叶片表面的硫代葡萄糖苷进行了定量，并表明在菥蓂属植物叶片表面发现的硫代葡萄糖苷浓度足以被产卵的小菜蛾感知。
