白蚁共生菌固氮研究进展  

Research progress of nitrogen fixation of symbiotic bacteria in termites

作　　者：王亚召 嵇保中[1] 刘曙雯 丁芳[1] 

机构地区：[1]南京林业大学南方现代林业协同创新中心,南京林业大学林学院,南京210037 [2]南京中山陵园管理局,南京210014

出　　处：《应用与环境生物学报》2016年第2期342-349,共8页Chinese Journal of Applied and Environmental Biology

基　　金：南京林业大学南方现代林业协同创新中心资助项目;高等学校博士学科点专项科研基金项目(20123204110001);江苏省自然科学基金项目(BK2012816);南京市建委和中山陵园管理局资助课题(201409);江苏高校优势学科建设工程项目(164010641);江苏省普通高校学术学位研究生科研创新计划项目(KYLX150911)资助~~

摘　　要：白蚁是寡氮营养型生物,食物中缺乏氮素营养,因此消化道内共生菌固氮对于白蚁的生存至关重要.本文从固氮活性检测及菌种分离鉴定、固氮酶基因筛查、固氮活性的影响因子、白蚁与固氮菌的关系等方面介绍白蚁共生菌固氮的研究进展:NifH基因高度保守,适用于固氮菌多样性研究;白蚁nifH基因序列在同属种类间较相似,但在科水平上存在分化;白蚁nifH基因多样性受白蚁生活类型及其系统发育地位影响,且与不同白蚁消化道内共生的原生动物区系相关;低等白蚁固氮能力较强,高等白蚁没有或固氮能力较弱,同种白蚁不同品级个体因食性选择不同固氮能力存在差异;食物含氮量与共生菌固氮活性具有较好的补偿性,两者呈负相关关系.后肠囊是主要固氮场所,固氮菌种类多为兼性厌氧菌,与白蚁之间存在联合固氮关系.应用共生原生动物和共生固氮菌协同作用的碳氮代谢理论可揭示白蚁共生菌固氮活性与原生动物区系之间的关系.白蚁共生固氮的研究不仅可解释昆虫的营养生理,还可为其他昆虫的生物固氮研究提供参考.固氮酶基因检测为固氮菌种类调查和系统进化分析提供了便利,可为白蚁内生固氮菌资源开发提供依据.关于高等白蚁体内固氮菌附生场所、固氮菌区系与蚁巢基质或食物的关系等均需进一步研究.Termites are oligonitrotrophs and usually thrive on a nitrogen-poor diet. Therefore, nitrogen fixation of symbiotic bacteria in the digestive tract is essential for the survival of termites. This paper reviews the research progress of the nitrogen fixation of symbiotic bacteria in termites in terms of the assay of nitrogen-fixing activity and the species identification of symbiotic bacteria, the screening of nif H genes, the impact factors of the nitrogen-fixing activity, and the relationship between termites and nitrogen-fixing bacteria. The nif H gene is highly conserved and used to analyze the diversity of nitrogenfixing bacteria. In termites, the sequence of nif H gene is of high similarity among the same genera individuals, but with differentiations on the family level. The phylogenetic diversity of nif H gene is infl uenced by the living type of termites and their phylogenetic status. Furthermore, it is related with the symbiotic protozoan fauna in the digestive tract. In general, the lower termites have stronger nitrogen fixation ability than the higher ones. Even in the same species, significant difference of nitrogen fixation ability exists among different individual castes. The differences may relate with food variety and nitrogenfixing activity. There is significant complementation and approximate negative correlation between the nitrogen content of food and the nitrogenase activity. The hindgut intestinal sac is shown to be the main site of nitrogen fixation, and most nitrogenfixing bacteria species are facultative anaerobic bacteria. These bacteria cooperate with their hosts to fulfil nitrogen fixation. The carbon and nitrogen metabolism theory based on the synergistic reaction between symbiotic protozoan and nitrogenfixing bacteria may throw light on the relationship between symbiotic protozoan fauna and the nitrogen-fixing activity of symbiotic nitrogen-fixing bacteria. The study of symbiotic nitrogen fixation in termites can not only explain the nutrition physiology of insects, but also provide re

关 键 词：白蚁 固氮 共生菌 NIFH基因 联合固氮 后肠囊 兼性厌氧 

分 类 号：Q965[生物学—昆虫学] Q93