Li Xiao, Qu Ming-Jing, Zhang Yi, Li Jian-Wen, Liu Tong-Xian
State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University, Yangling, China.
Shandong Peanut Research Institute, Qingdao, Shandong, China.
Front Physiol. 2018 Feb 13;9:87. doi: 10.3389/fphys.2018.00087. eCollection 2018.
Neuropeptide F (NPF) signaling systems are widespread and highly evolutionarily conserved from vertebrates to invertebrates. In fact, NPF has been identified in many insect species and plays regulatory roles in diverse physiological processes, such as feeding, learning, reproduction and stress responses. NPF operates by interacting with the NPF receptor (NPFR). Here, we characterized and determined the presumed role of NPF signaling in the wingless parthenogenetic pea aphid, . Quantitative real-time reverse transcription-PCR (qRT-PCR) revealed that the expression levels of both NPF and NPFR transcripts varied across developmental stages, which implies that the NPF signaling system might participate in the developmental regulation of aphid physiological processes or behaviors. The NPF transcript was mainly detected in the head but not in the gut, whereas the NPFR transcript was mainly detected in both the gut and head. In addition, the NPF transcript levels were markedly up-regulated in starved aphids compared with satiated aphids, and the transcript levels recovered after re-feeding. In contrast, the NPFR transcript levels remained stable in starved and re-fed aphids. Furthermore, RNAi knockdown by the injection of NPF dsRNA into wingless adult aphids significantly reduced their food intake. Further analysis of the modification of aphid feeding behavior on broad bean plants using electrical penetration graphs (EPGs) revealed that both the probing time and the total duration of phloem activity decreased significantly in the NPF treatment group. These results indicated a lower appetite for food after NPF knockdown, which could explain the reduction in aphid food intake. NPF silencing was also shown to reduce reproduction but not survival in aphids. Overall, the results of these experiments suggest that NPF plays an important role in regulation of feeding in .
神经肽F（NPF）信号系统广泛存在，从脊椎动物到无脊椎动物都具有高度的进化保守性。事实上，NPF已在许多昆虫物种中被鉴定出来，并在多种生理过程中发挥调节作用，如进食、学习、繁殖和应激反应。NPF通过与NPF受体（NPFR）相互作用发挥作用。在此，我们对无翅孤雌生殖豌豆蚜中NPF信号的假定作用进行了表征和确定。定量实时逆转录PCR（qRT-PCR）显示，NPF和NPFR转录本的表达水平在不同发育阶段有所变化，这意味着NPF信号系统可能参与蚜虫生理过程或行为的发育调节。NPF转录本主要在头部检测到，而在肠道中未检测到，而NPFR转录本主要在肠道和头部均检测到。此外，与饱腹蚜虫相比，饥饿蚜虫中NPF转录本水平显著上调，重新进食后转录本水平恢复。相比之下，饥饿和重新进食的蚜虫中NPFR转录本水平保持稳定。此外，通过向无翅成年蚜虫注射NPF双链RNA进行RNA干扰敲低，显著降低了它们的食物摄入量。使用电穿透图（EPG）对豌豆蚜在蚕豆植株上取食行为的变化进行进一步分析发现，NPF处理组的刺探时间和韧皮部活动总持续时间均显著减少。这些结果表明，NPF敲低后蚜虫对食物的食欲降低，这可以解释蚜虫食物摄入量的减少。NPF沉默还显示会降低蚜虫的繁殖力，但不影响其存活率。总体而言，这些实验结果表明，NPF在豌豆蚜的进食调节中起重要作用。
