Liu Shi-Huo, Li Hong-Fei, Yang Yang, Wei Dong, Jiang Hong-Bo, Dou Wei, Yuan Guo-Rui, Wang Jin-Jun
Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, 400716, China.
Academy of Agricultural Sciences, Southwest University, Chongqing, 400716, China.
AMB Express. 2018 Jan 11;8(1):5. doi: 10.1186/s13568-017-0533-8.
Phormicins belong to defensin family, which are important antimicrobial peptides (AMPs) in insects. These AMPs are inducible upon challenging by immune triggers. In the present study, we identified the cDNA of a phormicin gene (BdPho) in the oriental fruit fly, Bactrocera dorsalis (Hendel), a ruinous agricultural pest causing great economic losses to fruits and vegetables. The cDNA of BdPho contains a 282 bp open reading frame encoding 93 amino acid residues, and the predicted molecular weight and isoelectric point of BdPho peptide were 9.83 kDa and 7.54, respectively. Quantitative real-time PCR analyses showed that the transcription level of BdPho was the highest in adult during different developmental stages and was the highest in abdomen among adult tagmata. Moreover, BdPho was highly expressed in fat body among different tissues, both in female and male adult. The mRNA level of BdPho was significantly up-regulated to 7.46- and 14.53-fold at 3 and 6 h after the insects were challenged with peptidoglycans from Escherichia coli (PGN-EB), respectively, suggesting its antimicrobial activity against Gram-negative microorganisms. Furthermore, the expression level of BdPho was significantly up-regulated to 3.83-fold after mating, suggesting that female adults might enhance their immunity by up-regulating the expression level of BdPho during mating. These results firstly describe the basic properties of the phormicin gene from B. dorsalis, and lay the foundation for investigating functional properties of AMPs and exploring the molecular mechanisms in the immune system.
福米辛属于防御素家族，是昆虫体内重要的抗菌肽。这些抗菌肽在受到免疫触发因素刺激时可被诱导产生。在本研究中，我们鉴定出了东方果实蝇（Bactrocera dorsalis (Hendel)）中一种福米辛基因（BdPho）的cDNA，东方果实蝇是一种毁灭性农业害虫，给水果和蔬菜造成巨大经济损失。BdPho的cDNA包含一个282 bp的开放阅读框，编码93个氨基酸残基，预测的BdPho肽分子量和等电点分别为9.83 kDa和7.54。定量实时PCR分析表明，BdPho在不同发育阶段的成虫中转录水平最高，在成虫体节中腹部的转录水平最高。此外，BdPho在不同组织中，无论雌雄成虫，在脂肪体中均高度表达。在用来自大肠杆菌的肽聚糖（PGN-EB）攻击昆虫后3小时和6小时，BdPho的mRNA水平分别显著上调至7.46倍和14.53倍，表明其对革兰氏阴性微生物具有抗菌活性。此外，交配后BdPho的表达水平显著上调至3.83倍，表明雌性成虫可能在交配过程中通过上调BdPho的表达水平来增强免疫力。这些结果首次描述了来自桔小实蝇的福米辛基因的基本特性，为研究抗菌肽的功能特性和探索免疫系统中的分子机制奠定了基础。
