不同食物调控下烟草甲幼虫肠道菌群多样性的解析

Consuming different diets affects the gut bacterial diversity of Lasioderma serricorne larvae

摘要:

【背景】 昆虫肠道细菌在宿主的发育、营养代谢及免疫防御中发挥关键作用，其群落组成受食物来源显著影响。然而，不同食料条件下烟草甲(Lasioderma serricorne)幼虫肠道菌群多样性的研究尚不充分。【目的】 解析烟草甲幼虫肠道细菌多样性与其食源的内在关联，并对可培养共生菌进行分离鉴定。【方法】 基于PacBio SMRT平台的16S rRNA基因全长测序分析人工饲料组(SL组)、烟草驯化组(YC组)及野生环境组(WF组)烟草甲幼虫肠道细菌的群落结构。通过RT-qPCR技术研究肠杆菌属(Enterobacter)、沃尔巴克氏体属(Wolbachia)和杀雄菌属(Arsenophonus)这3种共生菌在3种不同食料条件下的表达量变化。同时，使用4种功能各异的培养基进行体外分离培养，筛选并鉴定出可培养的优势菌群。【结果】 三组肠道菌群OTU数量差异显著(SL组174个、YC组115个、WF组62个)。α多样性指数表明组间差异显著(SL > YC > WF, P < 0.05)。属水平上，SL组优势菌为Enterobacter (61.43%)、Wolbachia (13.12%)和肠球菌属(Enterococcus) (19.34%)；YC组以Wolbachia (87.09%)和Enterococcus (11.88%)为主；WF组则以Arsenophonus (97.91%)为绝对优势菌。RT-qPCR定量结果进一步验证了Enterobacter、Wolbachia及Arsenophonus在3组中的表达量差异。通过4种功能培养基的分离培养，获得13株可培养菌株并构建系统发育树，鉴定为泛菌属(Pantoea) (SL1, YC5)、不动杆菌属(Acinetobacter) (SL6, YC1, WF2, WF8, WF10)、Enterobacter (CB2)、微小杆菌属(Exiguobacterium) (SL5, YC3)及Enterococcus (WF6, YCL, WFL)。【结论】 本研究通过多维分析阐明了食源对烟草甲幼虫肠道菌群结构的塑造作用，为基于肠道微生物调控的害虫绿色防控策略提供了新思路。

Abstract:

[Background] Gut bacteria play crucial roles in the development, nutrient metabolism, and immune defenses of host insects, with their community composition being significantly influenced by diet sources. However, the research on the diversity of gut microbiota in Lasioderma serricorne larvae under different dietary conditions remains limited. [Objective] To elucidate the intrinsic relationship between gut bacterial diversity and diet sources in L. serricorne larvae and isolate and identify culturable symbiotic bacteria. [Methods] Full-length 16S rRNA gene sequencing was performed on the PacBio SMRT platform to analyze the community structure of gut bacteria in L. serricorne larvae in the artificial feed (SL) group, tobacco domestication (YC) group, and wild environment (WF) group. RT-qPCR was employed to quantify the expression levels of three symbiotic bacteria, Enterobacter, Wolbachia, and Arsenophonus, under the three dietary conditions. Culturable dominant bacteria were isolated and identified via four functionally distinct media. [Results] The number of gut microbiota OTUs varied significantly among different groups (SL: 174 OTUs; YC: 115 OTUs; WF: 62 OTUs). Alpha diversity indices confirmed significant intergroup differences (SL > YC > WF, P < 0.05). At the genus level, the dominant bacteria were Enterobacter (61.43%), Wolbachia (13.12%), and Enterococcus (19.34%) in the SL group, Wolbachia (87.09%) and Enterococcus (11.88%) in the YC group, and Arsenophonus (97.91%) in the WF group. RT-qPCR validated the differential expression of Enterobacter, Wolbachia, and Arsenophonus across groups. Thirteen culturable strains were isolated and phylogenetically identified as Pantoea (SL1 and YC5), Acinetobacter (SL6, YC1, WF2, WF8, and WF10), Enterobacter (CB2), Exiguobacterium (SL5 and YC3), and Enterococcus (WF6, YCL, and WFL). [Conclusion] This multi-dimensional analysis demonstrates how diets shape the gut microbiota structure of L. serricorne larvae, providing new insights for developing gut microbiota-based eco-friendly strategies for pest management.