昆虫病原线虫共生细菌共生性的分子生物学研究进展

嗜线虫致病杆菌属Xenorhabdus和发光杆菌属Photorhabdus细菌隶属肠杆菌科Enterobacteriaceae,对多种害虫致病能力强,分别与斯氏属Steinernema和异小杆属Heterorhabditis昆虫病原线虫互惠共生。该两属共生细菌既存在对昆虫寄主的病原性,又存在与线虫寄主的共生性。共生细菌与其线虫寄主的共生性主要表现以下4方面：（1）细菌产生食物信号诱导滞育不取食的感染期线虫恢复;（2）细菌为线虫生长与繁殖提供营养;（3）细菌能于感染期线虫的肠道定殖与生长;（4）细菌产生杀线虫毒素杀死非共生线虫。本文综述了共生菌以上4方面的共生性及其相关的分子机制。

Advances in molecular biology of mutualism in symbiotic bacteria associated with entomopathogenic nematode

Current knowledge of mutualism between entomopathogenic nematodes,Xenorhabdus and Photorhabdus bacteria,and the molecular mechanisms involved in this,are reviewed.Xenorhabdus and Photorhabdus,members of the bacterial family Enterobacteriaceae,are highly virulent to a wide range of insect pests but have a mutualistic association with the entomopathogenic nematodes Steinernema and Heterorhabditis.These bacteria therefore engage in both pathogenic interaction with insect hosts and mutualistic interaction with nematode hosts during their life cycle.The bacteria provide four essential functions for their nematode hosts：（1） production of food signals to induce development of arrested,non-feeding infective nematode juveniles（IJs）,（2） production of nutrients to facilitate nematode growth and development,（3） colonization and growth within IJ nematodes,（4） production of nematicidal toxin capable of killing non-symbiotic nematodes.