The State Key Laboratory for Biology of Plant Diseases of Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China.
J Agric Food Chem. 2010 Feb 24;58(4):2410-8. doi: 10.1021/jf9037248.
The saliva of two cereal aphids, Sitobion avenae and Schizaphis graminum in third-instar nymphs, was collected after 24 h of feeding by 30 aphids, separately, on artificial diet sachets, and the salivary enzymes were determined. The result showed that polyphenol oxidase (PPO) existed in the saliva of both aphid species, and the enzymatic activities were 6.2 x 10(-3) U/g for S. avenae and 2.37 x 10(-1) U/g for S. graminum, revealing a 38-fold higher activity in the saliva of S. graminum than in the saliva of S. avenae. It was speculated that the higher PPO activity in S. graminum saliva was a contributing factor to the light yellow spot left on the feeding site of the wheat leaf by S. graminum; no such spot was left by S. avenae. After treatment of a wheat seedling with the saliva of S. avenae and S. graminum and PPO at the concentration of aphid saliva, transcript profiling data showed that aphid saliva and PPO significantly induced expression of the genes aos and fps. Because genes aos and fps encode the key enzymes in the defense signal pathways jasmonic acid and terpene signal pathways, respectively, it was deduced that PPO from aphid saliva, as the main elicitor, triggers an appropriate defense response in wheat through jasmonic acid and terpene signal pathways.
两种麦长管蚜和禾谷缢管蚜三龄若虫的唾液在 24 小时喂食 30 只蚜虫后，分别从人工饲料袋中收集，测定唾液酶。结果表明，多酚氧化酶（PPO）存在于两种蚜虫的唾液中，酶活性分别为 S. avenae 的 6.2 x 10(-3) U/g 和 S. graminum 的 2.37 x 10(-1) U/g，表明 S. graminum 唾液中的活性是 S. avenae 的 38 倍。推测 S. graminum 唾液中较高的 PPO 活性是 S. graminum 在小麦叶片取食部位留下浅黄色斑点的一个促成因素；而 S. avenae 则没有留下这样的斑点。用 S. avenae 和 S. graminum 的唾液和 PPO 处理小麦幼苗，浓度为蚜虫唾液的浓度，转录谱数据显示，蚜虫唾液和 PPO 显著诱导 aos 和 fps 基因的表达。由于 aos 和 fps 基因分别编码防御信号途径茉莉酸和萜烯信号途径中的关键酶，因此可以推断，来自蚜虫唾液的 PPO 作为主要的激发子，通过茉莉酸和萜烯信号途径在小麦中触发适当的防御反应。
