关键词: 立克次体属, 昆虫, 胞内共生菌, 分布, 传播, 功能, 基因组

Abstract: Rickettsia species are intracellular symbionts of eukaryotes that are well known for infecting and causing serious diseases in humans and other vertebrates. All known vertebrate associated Rickettsia bacteria are vectored by arthropods as part of their life-cycle, and many other Rickettsia species are found exclusively in arthropods without any secondary host. For convenience, we refer to the former as vertebrateRickettsia  and the latter as arthropod Rickettsia. Previous research efforts mainly focused on medically important vertebrate Rickettsia. The biological studies of arthropod Rickettsia were limited. In recent years, more efforts have been made on the insect symbiont Rickettsia and considerable achievements have been obtained. The insect symbiont Rickettsia   is distributed among insects, and two different localization patterns exist in the same insect species. It can transmit vertically through eggs, and horizontally through parasitic wasps and host plants. It can influence the host reproduction by male-killing and parthenogenesis. It has beneficial or detrimental effects on its hosts and can increase the tolerance of its hosts to high temperature and parasitic wasps, and is correlated with its hosts’ susceptibility to insecticides. The insect symbiont   Rickettsia has a reduced genome and might undergo considerable further reduction.

Key words: Rickettsia, insect, intracellular symbiont, distribution, transmission, function, genome