Plant-Mediated Interactions between Two Cereal Aphid Species: Promotion of Aphid Performance and Attraction of More Parasitoids by Infestation of Wheat with Phytotoxic Aphid Schizaphis graminum

Here, we investigated changes in physiological characteristics in wheat affected by phytotoxic-aphid Schizaphis graminum feeding and nonphytotoxic-aphid Sitobion avenae feeding. We also determined whether shared host-mediated interspecific interactions occur between S. graminum and S. avenae. S. graminum feeding but not S. avenae feeding induced significant chlorophyll loss and hydrogen peroxide accumulation in wheat. Gene-expression analysis and GC/MS metabonomic results indicated that S. graminum infestation induced stronger salicylic acid mediated defense responses than S. avenae did and significantly increased the contents of several amino acids in wheat leaves. Feeding on wheat preinfested with S. graminum significantly increased the reproduction of both aphids and shortened the development time of S. graminum. However, olfactometer bioassays showed that the parasitoid wasp Aphidius gifuensis was more attracted to the odors of S. graminum infested wheat than to those of control and S. avenae infested wheat. This study demonstrates that S. graminum and S. avenae feeding induced different defense responses and changes in plant nutritional quality. Additionally, plant-mediated interactions occurred between these cereal aphids.

本研究针对麦二叉蚜（Schizaphis graminum，产毒蚜虫）与麦长管蚜（Sitobion avenae，非产毒蚜虫）取食后小麦的生理特性变化展开探究，同时验证了二者之间是否存在共同宿主介导的种间互作关系。研究发现，麦二叉蚜取食可诱导小麦出现显著叶绿素流失与过氧化氢积累，而麦长管蚜取食则无此效应。基因表达分析与气相色谱-质谱联用（GC/MS）代谢组学结果显示，相较于麦长管蚜，麦二叉蚜侵染可诱导更强的水杨酸介导防御反应，并显著提升小麦叶片内多种氨基酸的含量。取食预先被麦二叉蚜侵染的小麦，可显著提升两种蚜虫的繁殖能力，并缩短麦二叉蚜的发育时长。不过，嗅觉仪生测结果显示，烟蚜茧蜂（Aphidius gifuensis）对麦二叉蚜侵染小麦的挥发物趋性显著强于健康小麦与麦长管蚜侵染小麦。本研究证实，麦二叉蚜与麦长管蚜取食可诱导小麦产生不同的防御反应与营养品质变化，且这两种麦蚜之间存在植物介导的种间互作关系。