Zhang Yong, Fan Jia, Francis Frédéric, Chen Julian
State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, P.R. China.
Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, Liege, Belgium.
Arch Insect Biochem Physiol. 2018 Apr;97(4). doi: 10.1002/arch.21446. Epub 2018 Jan 11.
Laccase 1 (Lac1), a polyphenol oxidase, has been proposed to be involved in insect iron metabolism and immunity responses. However, little information is available on the roles of Lac 1 in insect-plant interactions. The grain aphid Sitobion avenae is one of the most destructive pests of cereal, directly drawing phloem sap and transmitting viruses. In the present study, we first cloned the open reading frame (ORF) of Lac 1 from S. avenae, and the putative protein sequence was predicted to have a carboxyl-terminal transmembrane domain. We found that SaLac1 had higher expression levels in the fourth and adult stages using reverse transcription real-time quantitative PCR (RT-qPCR). SaLac 1 was highly expressed in the salivary gland and midgut and also in wingless compared with winged morphs. After feeding on aphid-resistant wheat with a high total phenol content, the expression level of SaLac 1 increased significantly. RNA interference (RNAi) by oral feeding successfully inhibited the transcript levels of SaLac 1, and the knockdown of Lac 1 significantly decreased the survival rate of S. avenae on aphid-resistant wheat. Our study demonstrated that S. avenae Lac1 was involved in the detoxification of phenolic compounds in wheat and was essential for the aphid to adapt to resistant plants.
漆酶1（Lac1）是一种多酚氧化酶，有人提出它参与昆虫的铁代谢和免疫反应。然而，关于Lac1在昆虫与植物相互作用中的作用，目前所知甚少。麦长管蚜是谷物最具破坏性的害虫之一，直接吸食韧皮部汁液并传播病毒。在本研究中，我们首先从麦长管蚜中克隆了Lac1的开放阅读框（ORF），预测的推定蛋白质序列具有羧基末端跨膜结构域。我们通过逆转录实时定量PCR（RT-qPCR）发现，SaLac1在第四龄期和成虫期表达水平较高。与有翅型相比，SaLac1在唾液腺和中肠以及无翅型中也高度表达。取食总酚含量高的抗蚜小麦后，SaLac1的表达水平显著增加。通过口服喂食进行RNA干扰（RNAi）成功抑制了SaLac1的转录水平，敲低Lac1显著降低了麦长管蚜在抗蚜小麦上的存活率。我们的研究表明，麦长管蚜Lac1参与了小麦中酚类化合物的解毒过程，对蚜虫适应抗性植物至关重要。
