昆虫内共生菌及其功能研究进展

Advances in endosymbionts and their functions in insects

昆虫内共生菌与宿主之间的互作关系已逐渐成为昆虫学的研究热点之一。昆虫内共生菌具有协助宿主营养代谢、逃避天敌攻击和增强抗药性等功能:通过协助宿主营养代谢,提供食物中缺乏的营养物质来弥补食物中营养物质的不足;分泌抗菌肽、毒素等物质以增强对外源寄生物等的防御能力,抑制对宿主的不利影响;同时,也可以增强宿主抗逆性,调控植物生理反应,抑制植物对宿主的不利影响;利用对抗逆性基因精确的表达调控来增强宿主抗药性等。因此,内共生菌介导的宿主生物学性状的改变,扩大了宿主昆虫的生态位,成为昆虫生长发育过程中的重要调控因子。目前,昆虫内共生菌的功能往往是通过研究宿主感染共生菌前后性状的变化而证实。近几年,转录组学、蛋白质组学、基因组学等技术的进步,促进了内共生菌与宿主昆虫共生机制研究的发展。通过研究内共生菌及其功能基因在昆虫种群动态中的作用,特别是内共生菌感染对宿主生殖、存活、适应环境能力的影响,将有利于揭示内共生菌与宿主的共生机制,并最终为开发新的防控技术提供理论依据。本文针对昆虫内共生菌的功能进行了综述,并对日后的研究方向进行了展望,提供了研究昆虫内共生菌与宿主互作关系的方法及建议。

Interactions between endosymbionts and their insect host have drawn much attention at present. Endosymbionts could facilitate their hosts to acquire additional nutrition, protect them from natural enemy and enhance their insecticide resistance. Their special roles include facilitating digestion of food or providing nutrients that were limited or lacking in the host diet, enhancing pathogen and parasitoid resistance through secretion of antimierobial peptides or toxin and strengthening resistance of their hosts by regulating physiological reaction and accurate expression of resistance genes. These facts strongly suggest that endosymbionts play an important role in regulating host development through mediating the biological characters to expand the host＇ s ecological niche. The functions of endosymbionts were analyzed through examination of changes in biological characters of host before and after infection. Recently, new techniques on transeriptomics, proteomics and genomics have promoted the research on mutualism mechanisms between symbionts and insect hosts. This will not only reveal the endosymbionts and their functional genes on host reproduction, survival, population dynamics and adaption to the environment, but also open new insight into potential biological roles of endosymbionts, providing new insight for biological control of pest insect.