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抗菌肽是一类具有广谱抗菌活性的小分子多肽,包括抗细菌、病毒和真菌。本研究以斜纹夜蛾Spodoptera litura(Fabricius)为研究对象,利用Real-timePCR和半定量RT-PCR检测了其体内两个重要抗菌肽基因Cecropin和Moricin的时空表达模式及其对微生物的敏感性。Real-timePCR检测结果表明,抗菌肽基因Cecropin和Moricin在斜纹夜蛾各个龄期(1,2,3,4,5和6龄幼虫、蛹、成虫)都有表达,随着龄期的增长,表达量逐渐增加,6龄幼虫中表达量达到最高。半定量RT-PCR检测表明,抗菌肽基因Cecropin和Moricin在7个不同组织(气管、卵巢、马氏管、体壁、中肠、脂肪体和血细胞)中都有表达,Cecropin在脂肪体中表达量最高,而Moricin在血细胞中表达量相对较高;RT-PCR检测表明,Cecropin和Moricin的表达在大肠杆菌Escherichia coli诱导后迅速上升,其中诱导后8h达到高峰期,一直持续到48h。不同病原微生物(大肠杆菌E.coli、金黄色葡萄球菌Staphyloccocus aureus和白僵菌Beauveria bassiana)分别诱导后,Real-timePCR检测表明,斜纹夜蛾抗菌肽基因Cecropin和Moricin对大肠杆菌的刺激最为敏感。本研究结果为进一步研究斜纹夜蛾抗菌肽基因Cecropin和Moricin的功能奠定基础。
Antibacterial peptides are a class of small molecule peptides with broad spectrum antibacterial activity, including anti-bacterial, viral and fungal. In this study, Spodoptera litura (Fabricius) was used as the research object. The temporal and spatial expression patterns of Cecropin and Moricin, as well as their sensitivity to microorganisms, were detected by Real-time PCR and semi-quantitative RT-PCR. Real-time PCR results showed that the antimicrobial peptide genes Cecropin and Moricin were expressed in all stages of Spodoptera litura (1, 2, 3, 4, 5 and 6 instar larvae, pupae and adult). With the increase of age, The expression level gradually increased, reaching the highest level in 6th instar larvae. Semi-quantitative RT-PCR analysis showed that Cecropin and Moricin were expressed in seven different tissues (trachea, ovary, Markovs, wall, midgut, fat body and blood cells), and Cecropin was expressed in fat body While the expression of Moricin was relatively high in blood cells. RT-PCR results showed that the expression of Cecropin and Moricin increased rapidly after Escherichia coli was induced in E.coli. The expression reached the peak at 8h after induction, and continued until 48h. After different pathogenic microorganisms (E.coli, Staphyloccocus aureus and Beauveria bassiana) were induced respectively, Real-time PCR showed that Cecropin and Moricin were the most sensitive to Escherichia coli. The results of this study lay the foundation for the further study of the function of Cecropin and Moricin in Spodoptera litura.