Exploration of molecular mechanisms underlying the interaction between host insects and symbiotic bacteria and development of basic technology for the application

由于雄性后代在胚胎发育过程中选择性死亡，一些螺旋体导致其宿主昆虫（包括果蝇）的性别比例偏向雌性。本研究从2个杀雄螺原体和1个非杀雄螺原体中分离出3个亲缘关系较近的噬菌体，并测定了它们的全基因组序列。每个噬菌体基因组包含5个序列，这些序列与密切相关的螺旋体的推定毒力基因相似。总体而言，三种噬菌体的密度动态表现出不同的模式。一种基因的表达水平在感染了杀雄螺原体的成虫体内比感染了非杀雄螺原体的成虫体内高10倍左右。

Some spiroplasmas cause female-biased sex ratios of their host insects including Drosophila fruit flies, as a result of selective death of the male offspring during embryogenesis. In this study, three closely related bacteriophages were isolated from two male-killing spiroplasmas and a non-male-killing one, and their whole genome sequences were determined. Each phage genome included five sequences with similarity to putative virulence genes of closely related spiroplasma. In general, density dynamics of the three phages showed different pattern. The expression levels of a gene were about 10 times higher in adult flies infected with male-killing spiroplasma than in those infected with non-male-killing one.