食料对烟草甲体内真菌群落结构及多样性的影响

Diets influence the structure and diversity of the fungal community in the tobacco beetle Lasioderma serricorne

摘要:

目的 探究不同食料对烟草甲体内真菌群落结构和多样性的影响，为基于微生物调控的仓储害虫绿色防控策略提供理论依据。方法 基于PacBio SMRT测序平台，采用内转录间隔区(internal transcribed spacer, ITS)全长扩增子测序技术对比分析人工饲料组(SL)、烟草驯化组(YC)和野生环境组(WF) 3组实验中烟草甲体内真菌的群落结构特征。运用传统培养方法分离可培养真菌，并通过荧光定量PCR技术定位核心共生菌Symbiotaphrina kochii的组织表达模式。结果 群落结构特征分析显示，SL组、YC组和WF组分别鉴定出35、32和15个操作分类单元(operational taxonomic unit, OTU)，3组共有的核心OTUs占比分别为31.43%、34.38%、73.33%。多样性分析结果表明，SL组的Sobs指数(29.00±1.13)显著高于YC组(16.17±2.30)和WF组(12.33±1.33) (P<0.001)。Symbiotaphrina是3组共有核心功能菌群，其相对丰度均超过81.000 0%。曲霉属(Aspergillus)和耐干霉属(Xeromyces)是SL组和YC组的特征菌属，而Symbiotaphrina buchneri和Symbiotaphrina microtheca则形成了YC组和WF组特异性进化支。通过传统真菌分离技术，成功分离出8株子囊菌门真菌，其中包括Symbiotaphrina (3株)、Talaromyces (3株)和Penicillium (2株) 3个属。组织特异性表达证实，S. kochii在菌胞体中的表达量(10.42±1.03)显著高于脂肪体(0.74±0.08)和中肠(0.31±0.01)组织(P<0.001)，证实其胞内定殖特性。结论 本研究揭示了食料类型通过“营养-菌群”互作网络调控烟草甲体内真菌群落的构建，证实了Symbiotaphrina属在宿主适应性进化中的关键作用，为构建基于微生物互作网络精准调控的害虫治理新技术提供了理论依据与关键靶标。

Abstract:

Objective This study investigates the effects of various diets on the structure and diversity of the fungal community in the tobacco beetle Lasioderma serricorne, aiming to provide a theoretical basis for developing green control strategies for stored-product pests through microbial regulation.Methods The PacBio SMRT platform was used for full-length internal transcribed spacer (ITS) amplicon sequencing, on the basis of which the community structure characteristics of fungi in L. serricorne were compared among three groups: artificial feed (SL), tobacco domestication (YC), and wild environment (WF). Additionally, culturable fungi were isolated via the culture method, and the tissue expression pattern of the core symbiotic fungus Symbiotaphrina kochii was localized by RT-qPCR.Results SL, YC, and WF groups contained 35, 32, and 15 operational taxonomic units (OTUs), respectively. The core OTUs shared by the three groups accounted for 31.43%, 34.38%, and 73.33% in SL, YC, and WF groups, respectively. The Sobs index of the SL group was 29.00±1.13, which was higher than those of the YC group (16.17±2.30) and WF group (12.33±1.33) (P<0.001). Symbiotaphrina was the core functional group shared by the three groups, and its relative abundance was more than 81.000 0% in all the three groups. Aspergillus and Xeromyces were the characteristic genera of the SL and YC groups, while Symbiotaphrina buchneri and Symbiotaphrina microtheca formed the evolutionary clades specific to the YC and WF groups. Eight Ascomycota strains were isolated via the culture method, belonging to three genus: Symbiotaphrina (three strains), Talaromyces (three strains), and Penicillium (two strains). Tissue-specific expression analysis confirmed the higher expression level of S. kochii in mycetocytes (10.42±1.03) than in the fat body (0.74±0.08) and midgut (0.31±0.01) (P<0.001), validating its intracellular colonization.Conclusion This study for the first time reveals that diets regulate the fungal community assembly in L. serricorne through a “nutrient-microbiota” interaction network and demonstrates the pivotal role of Symbiotaphrina in adaptive evolution of the host. These findings establish a theoretical foundation and provide critical targets for developing precision pest control technologies based on targeted modulation of microbial interaction networks.