Abstract Lysozymes play important roles in the innate immune response against pathogen infections of insects. In this study, i-type and c-type lysozymes (LsLysI and LsLysC) were identified from the cigarette beetle, Lasioderma serricorne. Both genes were highly expressed in late larvae and pupae, especially in the fat body and integument. The expression of LsLysI and LsLysC was induced by 20-hydroxyecdysone. The expression levels of both LsLys genes were significantly upregulated after peptidoglycan (PGN) exposure and gram-positive bacterium Staphylococcus aureus infections. RNA interference (RNAi)-mediated knockdown of LsLysI or/and LsLysC in 5th instar larvae reduced lysozyme levels and disrupted the larva-to-pupa molt. Knockdown of LsLysI or LsLysC alone, and co-suppression of both genes, increased larval mortality by 13.3%, 21.1%, and 43.3% after S. aureus infection. The results demonstrated that LsLysI and LsLysC play key roles in a successful larva-to-pupa transition and in the innate immune response of L. serricorne.

中文翻译：

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Lasioderma serricorne（鞘翅目：Anobiidae）的幼虫-蛹转变和抗菌免疫涉及两种溶菌酶

摘要 溶菌酶在针对昆虫病原体感染的先天免疫反应中起重要作用。在本研究中，从卷烟甲虫 Lasioderma serricorne 中鉴定出 i 型和 c 型溶菌酶（LsLysI 和 LsLysC）。这两个基因在晚期幼虫和蛹中均高度表达，尤其是在脂肪体和体被中。LsLysI 和 LsLysC 的表达由 20-羟基蜕皮激素诱导。在肽聚糖 (PGN) 暴露和革兰氏阳性菌金黄色葡萄球菌感染后，两种 LsLys 基因的表达水平均显着上调。RNA 干扰 (RNAi) 介导的 LsLysI 或/和 LsLysC 在 5 龄幼虫中的敲低降低了溶菌酶水平并破坏了幼虫到蛹的蜕皮。单独敲低 LsLysI 或 LsLysC，以及共同抑制这两种基因，幼虫死亡率分别增加了 13.3%、21.1% 和 43。3% 金黄色葡萄球菌感染后。结果表明，LsLysI 和 LsLysC 在幼虫到蛹的成功转变和丝角乳杆菌的先天免疫反应中起着关键作用。