西花蓟马取食、机械损伤和外源物质诱导对番茄植株次生物质及西花蓟马解毒酶的影响
Effects of thrips feeding, mechanical wounding and induction by exogenous substances on the secondary metabolites of tomato plants and the activities of detoxifying enzymes in Frankliniella occidentalis

为阐明寄主植物番茄受害虫西花蓟马Frankliniella occidentalis取食、机械损伤及外源物质茉莉酸和水杨酸甲酯诱导后次生物质含量的变化，以及害虫如何通过调整体内解毒酶活性适应植物的防御反应，采用生化分析法测定了各诱导处理下次生物质黄酮、总酚和单宁含量及西花蓟马体内解毒酶多功能氧化酶（MFO）、乙酰胆碱酯酶（AchE）、谷胱甘肽S-转移酶（GSTs）和羧酸酯酶（CarE）活性的变化。结果表明：番茄叶片在各诱导处理下黄酮含量在36 h和48 h时均显著高于对照，相应时间段茉莉酸处理与水杨酸甲酯处理的黄酮含量升高最显著，分别达32.07 mg/g和31.76 mg/g；各诱导处理后24 h和36 h时，单宁和总酚含量均有不同程度下降，但总酚含量在48 h时显著升高，其中虫害处理增加最显著，达34.51 mg/g。取食各种诱导处理番茄植株6 h时，西花蓟马体内MFO活性均升高，AchE活性均受到抑制；取食除机械损伤外的其它诱导处理叶片6 h后，西花蓟马体内GSTs活性均被抑制，CarE活性均显著上升，其中取食水杨酸甲酯处理叶片的西花蓟马体内GSTs活性下降幅度最大，而CarE活性升高最显著，分别为3 882.35 U/mg和106.33 U/mg。表明各诱导处理不仅可以使番茄次生物质含量发生变化，诱导植株产生防御反应，也会使西花蓟马改变解毒酶的活性以适应寄主植物的诱导抗性，即寄主植物和害虫通过防御与反防御相互适应。
To explore the changes of secondary metabolites in tomato plants induced by thrips feeding, mechanical wounding and the exogenous substances jasmonic acid (JA) and methyl salicylate (MeSA) and investigate how pests adapt to plants' defensive responses through regulation of its detoxification enzyme activities, biochemical analysis was carried out to measure the changes of secondary metabolites (including tannins, total phenolics and flavones) in leaves of tomato plants under different induction treatments; moreover, the activities of mixed-functional oxidase (MFO), carboxylesterase (CarE), glutathione S-transferase (GSTs) and acetylcholinesterase (AchE) in Frankliniella occidentalis were also measured. The results showed that the contents of flavonoids in leaves of tomato plants under all induction treatments were much higher than that of the control at 36 h and 48 h. In all treatments, JA and MeSA induced higher contents of flavonoids at the same time point, which were 32.07 mg/g and 31.76 mg/g, respectively. The contents of tannin and total phenolics decreased at 24 h and 36 h, while the content of total phenolics rose significantly at 48 h; among all treatments, thrips feeding induced the highest level of phenolics (34.51 mg/g). In F. occidentalis fed with leaves of tomato plants under various induction treatments, the activity of MFO increased at 6 h, while the activities of AchE decreased at 6 h. Except for mechanical wounding, the activity of GSTs in F. occidentalis decreased under all other treatments, while CarE increased significantly at 6 h; moreover, the activities of GSTs and CarE in those fed with leaves of MeSA-treated plants changed rapidly:GSTs sharply decreased to 3 882.35 U/mg, while CarE dramatically increased to 106.33 U/mg. Collectively, the results indicated that different induction treatments could not only induce changes of secondary metabolites in tomato plants, but also mediate F. occidentalis adaptation to