Acevedo Flor E, Stanley Bruce A, Stanley Anne, Peiffer Michelle, Luthe Dawn S, Felton Gary W
Department of Entomology, The Pennsylvania State University, 501 Agricultural Sciences and Industries Building, University Park, PA 16802, USA.
Section of Research Resources, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
Insect Biochem Mol Biol. 2017 Jul;86:81-92. doi: 10.1016/j.ibmb.2017.06.001. Epub 2017 Jun 4.
Lepidopteran larvae secrete saliva on plant tissues during feeding. Components in the saliva may aid in food digestion, whereas other components are recognized by plants as cues to elicit defense responses. Despite the ecological and economical importance of these plant-feeding insects, knowledge of their saliva composition is limited to a few species. In this study, we identified the salivary proteins of larvae of the fall armyworm (FAW), Spodoptera frugiperda; determined qualitative and quantitative differences in the salivary proteome of the two host races-corn and rice strains-of this insect; and identified changes in total protein concentration and relative protein abundance in the saliva of FAW larvae associated with different host plants. Quantitative proteomic analyses were performed using labeling with isobaric tags for relative and absolute quantification followed by liquid chromatography-tandem mass spectrometry. In total, 98 proteins were identified (>99% confidence) in the FAW saliva. These proteins were further categorized into five functional groups: proteins potentially involved in (1) plant defense regulation, (2) herbivore offense, (3) insect immunity, (4) detoxification, (5) digestion, and (6) other functions. Moreover, there were differences in the salivary proteome between the FAW strains that were identified by label-free proteomic analyses. Thirteen differentially identified proteins were present in each strain. There were also differences in the relative abundance of eleven salivary proteins between the two FAW host strains as well as differences within each strain associated with different diets. The total salivary protein concentration was also different for the two strains reared on different host plants. Based on these results, we conclude that the FAW saliva contains a complex mixture of proteins involved in different functions that are specific for each strain and its composition can change plastically in response to diet type.
鳞翅目幼虫在取食期间会在植物组织上分泌唾液。唾液中的成分可能有助于食物消化，而其他成分则被植物识别为引发防御反应的信号。尽管这些以植物为食的昆虫在生态和经济方面具有重要意义，但关于它们唾液成分的了解仅限于少数物种。在本研究中，我们鉴定了草地贪夜蛾（FAW）幼虫，即草地贪夜蛾（Spodoptera frugiperda）的唾液蛋白；确定了该昆虫两个寄主种群——玉米品系和水稻品系——唾液蛋白质组的定性和定量差异；并确定了与不同寄主植物相关的草地贪夜蛾幼虫唾液中总蛋白浓度和相对蛋白丰度的变化。使用等压标签相对和绝对定量标记，随后进行液相色谱 - 串联质谱分析进行定量蛋白质组学分析。总共在草地贪夜蛾唾液中鉴定出98种蛋白质（置信度>99%）。这些蛋白质进一步分为五个功能组：可能参与（1）植物防御调节、（2）植食性进攻、（3）昆虫免疫、（4）解毒、（5）消化以及（6）其他功能的蛋白质。此外，通过无标记蛋白质组学分析鉴定出草地贪夜蛾品系之间的唾液蛋白质组存在差异。每个品系中存在13种差异鉴定的蛋白质。在两个草地贪夜蛾寄主品系之间，11种唾液蛋白的相对丰度也存在差异，并且每个品系内与不同食物相关的蛋白也存在差异。在不同寄主植物上饲养的两个品系的总唾液蛋白浓度也不同。基于这些结果，我们得出结论，草地贪夜蛾唾液含有参与不同功能的复杂蛋白质混合物，这些蛋白质对每个品系都是特异性的，并且其组成可以根据食物类型发生可塑性变化。
