东方蜜蜂微孢子虫感染对中华蜜蜂免疫基因表达和血淋巴中糖水平的影响

Effects of Nosema ceranae on the expression of immune gene and haemolymph sugar levels of Apis cerana bees

【目的】东方蜜蜂微孢子虫Nosemaceranae主要感染蜜蜂的消化系统,它被认为是引起蜂群崩溃综合症(Colony collapse disorder,CCD)的主要原因之一。东方蜜蜂微孢子虫对新寄主西方蜜蜂Apis mellifera的影响已得到广泛的研究,但它对原宿主中华蜜蜂Apis cerana cerana影响的报到则相对较少。本实验以意大利蜜蜂Apis mellifera ligustica来源的东方蜜蜂微孢子虫感染中华蜜蜂,分析感病中华蜜蜂的免疫基因表达和血淋巴中糖含量变化,评价东方蜜蜂微孢子虫对中华蜜蜂健康的影响。【方法】利用荧光定量检测样本的免疫基因(vitellogenin、abaecin、apidaecin、hymenoptaecin、defensinl、defensin2和eater)表达量,分析东方蜜蜂微孢子虫的感染能否引起中华蜜蜂免疫应答。通过高效液相色谱法对样本的血淋巴进行糖浓度定量分析,检测其血淋巴中葡萄糖、海藻糖含量。【结果】所研究基因中,hymenoptaecin基因表达量在14日龄时感染组和对照组差异显著、vitellogenin基因表达量在7日龄时感染组和对照组间差异显著、defensin2基因表达量在7日龄和14日龄时感染组和对照组均差异显著,其他基因的表达量在均未达到显著水平;血淋巴中的葡萄糖与海藻糖的浓度在处理组和对照组间差异不显著。【结论】东方蜜蜂微孢子虫侵染中华蜜蜂后,hymenoptaecin、vitellogenin,defensin2基因在相应的日龄可对病原物应答,然而血淋巴中的葡萄糖和海藻糖的浓度不因侵染与否变化。

[Objectives] Nosema ceranae mainly infects the digestive system of honeybees and is also thought to be a factor that may lead to Colony Collapse Disorder （CCD）. The effects of N. ceranae on Apis mellifera have been intensively studied, however, there has been relatively little research on its effects on its original host, Apis cerana cerana. Workers of A. cerana cerana were infected by N. ceranae isolated from A. cerana cerana. We evaluated the impacts of N. ceranae on the health of A. cerana cerana by measuring the expression of immune genes and sugar concentration in the haemolymph. [Methods] The expression of immune genes, including vitellogenin、abaecin、apidaecin、hymenoptaecin、defensin1、defensin2 and eater, was measured in infected and uninfected bees to determine whether infection with N. ceranae induced an immune response. We used HPLC analysis to quantitatively analyze the haemolymph of infected and uninfected A. cerana cerana, and measured concentrations of trehalose and glucose in the haemolymph under the same HPLC conditions. [Results] Infected and uninfected bees of 14 and 7 days of age significantly differed in their expression of hymenoptaecin, vitellogenin, and defensin2, but the expression of other genes was not significantly different. The concentration of glucose and trehalose in the haemolymph of infected bees was not significantly different from that in uninfected bees. [Conclusion] Expression of the immune genes hymenoptaecin, vitellogenin and defensin2 is induced in Apis cerana cerana of 7 and 14 days of age by infection with N. ceranae, but the concentration of glucose and trehalose in the haemolymph is not affected by infection.