益蝽成虫肠道微生物群落结构及其碳源代谢功能

Community structure and carbon source metabolic function of the intestinal microbes of adult Picromerus lewisi(Hemiptera:Pentatomidae)

【目的】肠道微生物对宿主昆虫的代谢、生长发育及免疫等功能发挥着重要作用。本研究旨在探究益蝽Picromerus lewisi成虫肠道微生物群落结构及其碳源代谢能力。【方法】利用体外培养分离纯化益蝽成虫肠道微生物并进行分子生物学鉴定,利用Illumina高通量测序技术进行细菌16S rDNA和真菌ITS基因测序,解析益蝽成虫肠道细菌和真菌群落结构和多样性;利用PICRUSt和FUNGuild对细菌和真菌及其基因功能进行预测;利用Biolog ECO技术解析益蝽成虫肠道细菌和真菌的碳源代谢功能。【结果】共分离益蝽成虫肠道可培养优势细菌肠球菌属Enterococcus菌株10株,优势细菌为粪肠球菌E.faecalis。高通量测序结果表明,在门水平上,益蝽成虫肠道优势细菌为变形菌门(Proteobacteria)(相对丰度58.51%)和厚壁菌门(Firmicutes)(相对丰度38.92%);主要优势真菌为子囊菌门(Ascomycota)(相对丰度56.53%),其次是担子菌门(Basidiomycota)(相对丰度11.34%)。在属水平上,肠球菌属Enterococcus(相对丰度25.05%)为主要优势细菌属,其次是乳球菌属Lactococcus(相对丰度12.23%)、沙雷氏菌属Serratia(相对丰度11.48%)和普罗威登斯菌属Providencia(相对丰度2.38%);优势真菌属主要为Biappendiculispora(相对丰度18.30%),其次是枝孢菌属Cladosporium(相对丰度11.83%)、Vishniacozyma(相对丰度5.17%)和鬼笔属Phallus(相对丰度3.62%)。益蝽成虫肠道细菌和真菌群落结构具有较高的物种丰富度和多样性,以及较强的碳源代谢能力,可高效代谢α-环式糊精、L-丝氨酸、腐胺和D-苹果酸等27种碳源。功能预测显示,益蝽成虫肠道细菌主要分布于新陈代谢类群、环境信息处理类群和遗传信息处理类群等,真菌主要分布于未定义类群、植物腐生菌、未定义腐生菌、内生菌-植物病原菌、真菌寄生菌-未定义腐生菌、叶子腐生菌和动物病原菌-内生菌-植物病原菌-木质腐生菌类。【结论】益蝽成虫肠道细菌和真菌种类多、多样性高,在属水平,优势细菌为肠球菌属、乳球菌属、沙雷氏菌属和普罗威登斯菌属,优势真菌为Biappendiculispora、枝孢菌属、Vishniacozyma和鬼笔属,具有较强的碳源代谢能力。

【Aim】Intestinal microbes play important roles in metabolism,growth and development,and immunity in host insects.This study aims to explore the community structure of the intestinal microbes of Picromerus lewisi adults and their ability to metabolize carbon sources.【Methods】The intestinal microbes were isolated and purified from P.lewisi adults by in vitro culture and identified by molecular biology technologies.The bacterial 16S rDNA and fungal ITS genes were sequenced by Illumina high-throughput sequencing technology to analyze the structure and diversity of the intestinal bacterial and fungal communities of P.lewisi adults.PICRUSt and FUNGuild were used to predict the function of bacteria and fungi and their genes.Biolog ECO technique was used to analyze the carbon source metabolic function of the intestinal bacteria and fungi of P.lewisi adults.【Results】A total of 10 strains of Enterococcus sp.were isolated from the intestinal culturable dominant bacteria of P.lewisi,and the dominant bacterium was E.faecalis.The results of high-throughput sequencing showed that the dominant phyla in the intestine of P.lewisi adults were Proteobacteria(relative abundance:58.51%)and Firmicutes(relative abundance:38.92%),and the most dominant fungal phylum was Ascomycota(relative abundance:56.53%),followed by Basidiomycota(relative abundance:11.34%).The most dominant bacterial genus in the intestine of P.lewisi adults was Enterococcus(relative abundance:25.05%),followed by Lactococcus(relative abundance:12.23%),Serratia(relative abundance:11.48%)and Providencia(relative abundance:2.38%),and the most dominant fungal genus was Biappendiculispora(relative abundance:18.30%),followed by Cladosporium(relative abundance:11.83%),Vishniacozyma(relative abundance:5.17%),and Phallus(relative abundance:3.62%).The community structure of the intestinal bacteria and fungi of P.lewisi adults showed high species richness and diversity,and strong metabolic ability on carbon sources,being able to efficiently metabolize 27 carbon sources includingα-cyclodextrin,L-serine,sutrescine,D-malic acid etc.Functional predictions showed that the intestinal bacterial taxa of P.lewisi adults were mainly distributed in metabolism,environmental information processing,genetic information processing etc.,and the fungal taxa were mainly distributed in unassigned taxa,plant saprotroph,undefined saprotroph,endophyte-plant pathogen,fungal parasite-undefined saprotroph,leaf saprotroph,and animal pathogen-endophyte-plant pathogen-wood saprotroph.【Conclusion】P.lewisi adults have a high variety and diversity of intestinal bacteria and fungi.The dominant bacterial genera were Enterococcus,Lactococcus,Serratia and Providencia,and the dominant fungal genera were Biappendiculispora,Cladosporium,Vishniacozyma and Phallus,with a strong metabolic ability on carbon sources.