马铃薯块茎蛾肠道细菌多样性及食性适应机理研究

Study on the insect insect gut bacterials has been concerned just because of the interaction between the insect gut bacterials and the meditate functions for insects, great achievements have been get on the gut microrganisms diversity and the mechanism for the feeding habitat adapty for theose insects feeding soly on the cellulose plants, but no resports on the gut bacterials diversity and the mechanism for the feeding habitat adapty for insects feeding both on the cellulose and amylum plants. The Potato Tuber Moth, Phthorimaea operculella Zeller, is an important pest insect of potato, it can feeding on leaf and tuber of potato, and it is a quarantine insect, the gut bacterials diversity and the mechanism for the feeding habitat adapty for potato tuber moth is unclear. This study will study the diversity and the predominant species of gut bacterials from the gut of those potato tuber moth larvae after the successive fed with potato leaf, potato tuber and leaf tuber combined feeds using the 16S rDNAaequencing. The catabolic function of the gut bacterials on the cellulose and amylum using the high depth metagenomics and metatranscriptomics techniques, in order to make clear on the feeding habitat adaption mechanisms for potato tuber moth. The resutls of this study will provide new idear for the study on the diversity of gut microorganisms and scientific bases for the insect control on potato tuber moth.

昆虫肠道细菌因其与昆虫间共生关系及其对昆虫的生理调节功能而备受关注，国内外对一些仅以纤维素为主要成份植物组织为食的昆虫肠道细菌多样性及食性适应机理等研究方面已取得了重要成果，但对能以纤维素和淀粉为营养成分植物组织为食的昆虫肠道细菌多样性及食性适应机理研究还未见报道。马铃薯块茎蛾是一种既能取食以纤维素为主要成分的马铃薯叶片、又能取食以淀粉为主要成分的马铃薯块茎的国际检疫性害虫，其肠道细菌多样性及食性的适应机制还不清楚。本项目拟以马铃薯块茎蛾为材料，采用16S rDNA扩增子测序法，研究继代取食马铃薯叶片、薯块、叶片和薯块混合寄主的马铃薯块茎蛾幼虫肠道细菌种类组成及优势种类；再通过高深度宏基因组测序及宏转录组技术研究肠道细菌对纤维素和淀粉的降解功能，探明马铃薯块茎蛾对富含纤维素的叶片和富含淀粉的薯块的适应机制。该研究结果将为马铃薯块茎蛾肠道微生物多样性研究及害虫防治提供新的思路和科学依据。

肠道菌多样性及对昆虫寄主调控是昆虫寄主适应机制研究的新方向。马铃薯块茎蛾既取食富含纤维素的叶片，还取食富含淀粉和茄碱的薯块，但机理尚不清楚。采用分离培养和宏基因组学法，研究了马铃薯块茎蛾幼虫肠道细菌组成及多样性。发现马铃薯块茎蛾肠道细菌优势门、科和属分别为变形菌门、γ-变形菌科、肠杆菌属，取食马铃薯块茎和叶片的块茎蛾肠道可培养细菌分别有4门10科12属16种和4门11科11属17种，其中变形菌门和厚壁菌门分别是取食块茎和叶片的块茎蛾肠道可培养细菌的优势菌门。粘质沙雷氏菌和乙酸钙不动杆菌、乙酸钙不动杆菌和栖木槿假单胞菌分别是取食马铃薯块茎和叶片的块茎蛾肠道可培养细菌的优势种。取食块茎和叶片的块茎蛾肠道产淀粉酶和纤维素酶细菌种类和丰度不同，取食块茎、叶片的种群肠道内产淀粉酶、纤维素酶和同时降解二者的细菌分别有5、3和4种与3、5和3种，取食块茎和叶片的块茎蛾肠道内降解淀粉和纤维素的可培养细菌优势种分别为乙酸钙不动杆菌和粘质沙雷氏菌。降解马铃薯茄碱碱α-茄碱的细菌有加拿大鞘氨醇杆菌Sphingobacterium canadense、谷氨酸杆菌Glutamicibacter halophytocola、藤黄色单胞菌Luteimonas chenhongjianii和鲁氏不动杆菌Acinetobacter lwoffii，降解α-卡茄碱的细菌有谷氨酸杆菌Glutamicibacter halophytocola，肠道菌降解酶是块茎蛾适应淀粉、纤维素及茄碱的主要机理，谷氨酸杆菌基因组中的GE000599、GE000600和GE000601参与α-茄碱和α-卡茄碱的降解。该研究探明了块茎蛾肠道细菌通过产生代谢淀粉和纤维素及茄碱的酶来适应寄主，揭示了块茎蛾肠道细菌调控其寄主适应的机制，回答了昆虫肠道细菌响应昆虫食性变化的科学问题，将丰富昆虫寄主适应机制，也将为害马铃薯块茎蛾防治提供依据。