Koga Ryuichi, Tsuchida Tsutomu, Sakurai Makiko, Fukatsu Takema
Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
FEMS Microbiol Ecol. 2007 May;60(2):229-39. doi: 10.1111/j.1574-6941.2007.00284.x. Epub 2007 Feb 22.
Multiple endosymbionts commonly coexist in the same host insects. In order to gain an understanding of the biological roles of the individual symbionts in such complex systems, experimental techniques for enabling the selective removal of a specific symbiont from the host are of great importance. By using the pea aphid-Buchnera-Serratia endosymbiotic system as a model, the efficacy, generality, and fitness consequences of selective elimination techniques at various antibiotic doses and under a variety of host genotypes were investigated. In all the disymbiotic aphid strains examined, the facultative symbiont Serratia was selectively eliminated by ampicillin treatment in a dose-dependent manner, suggesting a generality of the elimination technique irrespective of host genotype. However, fitness consequences of the Serratia elimination differed between the aphid strains, indicating substantial effects of host genotype. In all the disymbiotic aphid strains, the obligate symbiont Buchnera was selectively eliminated by rifampicin treatment irrespective of the antibiotic dose. However, the survival and reproduction of the Buchnera-free aphids varied in a dose-dependent manner, and the dose dependence was strikingly different between the aphid genotypes. These results provide a basis for the development of new protocols for manipulating insect endosymbiotic microbiota.
多种内共生体通常共存于同一宿主昆虫体内。为了了解在这种复杂系统中单个共生体的生物学作用，能够从宿主中选择性去除特定共生体的实验技术至关重要。以豌豆蚜-布赫纳氏菌-沙雷氏菌内共生系统为模型，研究了在不同抗生素剂量和多种宿主基因型条件下选择性消除技术的有效性、普遍性以及对适应性的影响。在所检测的所有双共生蚜虫品系中，兼性共生体沙雷氏菌通过氨苄青霉素处理以剂量依赖的方式被选择性消除，这表明消除技术具有普遍性，与宿主基因型无关。然而，沙雷氏菌消除对适应性的影响在蚜虫品系之间存在差异，表明宿主基因型有显著影响。在所有双共生蚜虫品系中，专性共生体布赫纳氏菌通过利福平处理被选择性消除，与抗生素剂量无关。然而，无布赫纳氏菌蚜虫的存活和繁殖以剂量依赖的方式变化，并且剂量依赖性在蚜虫基因型之间显著不同。这些结果为开发操纵昆虫内共生微生物群的新方案提供了基础。
