Department of Insects Genetics, Institute of Cytology and Genetics SB RAS, Novosibirsk 630090, Russia
Department of Insects Genetics, Institute of Cytology and Genetics SB RAS, Novosibirsk 630090, Russia.
J Exp Biol. 2019 Feb 22;222(Pt 4):jeb195347. doi: 10.1242/jeb.195347.
Maternally inherited intracellular bacteria cause both parasitic and mutualistic effects on their numerous insect hosts, including manipulating the host reproductive system in order to increase the bacteria spreading in a host population, and increasing the host fitness. Here, we demonstrate that the type of infection determines the effect on egg production as a proxy for fecundity, and metabolism of juvenile hormone (JH), which acts as gonadotropin in adult insects. For this study, we used six lineages carrying the nuclear background of interbred Bi90 lineage and cytoplasmic backgrounds with or without of different genotype variants. The MelCS genotype of decreases egg production in infected females in the beginning of oviposition and increases it later (from the sixth day after eclosion), whereas the MelPop strain causes the opposite effect, and the Mel, Mel2 and Mel4 genotypes of do not show any effect on these traits compared with uninfected Bi90 females. The intensity of JH catabolism negatively correlates with the fecundity level in the flies carrying both MelCS and MelPop The JH catabolism in females infected with genotypes of the Mel group does not differ from that in uninfected females. The effects of MelCS and MelPop infection on egg production can be levelled by the modulation of JH titre (via precocene/JH treatment of the flies). Thus, at least one of the mechanisms promoting the effect of on female fecundity is mediated by JH.
母系遗传的细胞内细菌对其众多昆虫宿主既有寄生作用，也有共生作用，包括操纵宿主生殖系统以增加细菌在宿主种群中的传播，并提高宿主适应性。在这里，我们证明了感染类型决定了其对产卵的影响，而产卵则可以作为繁殖力的代表，同时还影响了保幼激素（JH）的代谢，JH 在成年昆虫中充当促性腺激素。在这项研究中，我们使用了携带杂交 Bi90 系核背景和带有或不带有不同基因型变体的细胞质背景的六个谱系。 菌株的 MelCS 基因型在产卵初期会降低感染 的雌性产卵量，而在后期（羽化后第六天）会增加产卵量，而 MelPop 菌株则会产生相反的效果，与未感染的 Bi90 相比， 菌株的 Mel、Mel2 和 Mel4 基因型对这些特性没有任何影响。JH 分解代谢的强度与携带 MelCS 和 MelPop 的果蝇的生殖力水平呈负相关。感染 Mel 组基因型的雌性体内的 JH 分解代谢与未感染的雌性体内的 JH 分解代谢没有区别。感染 MelCS 和 MelPop 对产卵的影响可以通过调节 JH 浓度（通过 precocene/JH 处理果蝇）来平衡。因此，至少有一种促进 对雌性生殖力影响的机制是通过 JH 介导的。
