Oregon State University, 4017 Ag & Life Sciences Bldg., Corvallis, OR 97330, USA.
J Econ Entomol. 2012 Aug;105(4):1465-70. doi: 10.1603/ec11405.
The aphid Amphorophora agathonica Hottes (Hemiptera: Aphididae) is an important virus vector in red (Rubus idaeus L.) and black (Rubus occidentalis L.) raspberries in North America. Raspberry resistance to A. agathonica in the form of a single dominant gene named Ag1 has been relied upon to help control aphid-transmitted plant viruses; however, the mechanism of resistance to the insect is poorly understood. Aphid feeding was monitored using an electrical penetration graph on the resistant red raspberry 'Tulameen' and compared with a susceptible control, 'Vintage'. There were no differences in pathway feeding behaviors of aphids as they moved toward the phloem. Once in the phloem, however, aphids feeding on resistant plants spent significantly more time salivating than on susceptible plants, and ingested significantly less phloem sap. This suggests that a mechanism for resistance to A. agathonica is located in the phloem. Reduced ingestion of phloem may result in inefficient acquisition of viruses and is a likely explanation for the lack of aphid-transmitted viruses in plantings of resistant cultivars.
桃蚜 Amphorophora agathonica Hottes（半翅目：蚜科）是北美洲红（Rubus idaeus L.）和黑（Rubus occidentalis L.）覆盆子中的一种重要病毒载体。覆盆子对 A. agathonica 的抗性形式是单一显性基因 Ag1，它被用来帮助控制蚜虫传播的植物病毒；然而，对这种昆虫的抗性机制还知之甚少。使用电穿透图监测抗红覆盆子 'Tulameen' 和易感对照 'Vintage' 上的桃蚜取食情况。蚜虫在向韧皮部移动时，取食行为没有差异。然而，一旦进入韧皮部，取食抗性植株的蚜虫分泌唾液的时间明显长于取食易感植株的时间，并且摄入的韧皮部汁液明显减少。这表明，对 A. agathonica 的抗性机制位于韧皮部。韧皮部取食量减少可能导致病毒摄取效率降低，这可能是抗性品种种植中缺乏蚜虫传播病毒的原因。
