中华蜜蜂和意大利蜜蜂感染囊状幼虫病毒后免疫及发育相关基因表达比较

Comparison of expression of the genes associated with immunity and development between Apis cerana cerana and Apis mellifera ligustica infected with sacbrood virus

摘要:

【目的】本文旨在探究囊状幼虫病毒(sacbrood virus, SBV)对中华蜜蜂(Apis cerana cerana, 简称中蜂)和意大利蜜蜂(Apis mellifera ligustica, 简称意蜂)工蜂幼虫发育和免疫基因、营养代谢基因、抗病毒基因、细胞发育及代谢相关基因表达的影响。【方法】从蜂群中移取2日龄的中蜂和意蜂幼虫，在培养箱(34 ℃, RH 85%)进行人工饲养，3日龄时接种SBV病毒，每天观察记录死亡情况，并通过实时定量PCR (real-time quantitative polymerase chain reaction, RT-qPCR)检测4日龄和7日龄幼虫体内SBV基因相对表达量，及免疫基因(Apidaecin、Abaecin、Hymenoptaecin、Denfensin、Lys-1、Pgrp-lc、Kenny、Domeless)、营养代谢基因(Ilp1、Hex110、Vg)、抗病毒基因(Dis3、Dicer、Ago1)、细胞组成及发育调控基因(Vhdl、Co-1-iv)以及细胞代谢和调控基因(Mta1)的表达水平。【结果】通过分析比较发现，感染相同剂量的SBV后，中蜂幼虫在8日龄时全部死亡，意蜂幼虫则有部分羽化出房，并且同日龄中蜂幼虫体内SBV基因表达水平显著高于意蜂。与对照组相比，4日龄中蜂幼虫体内Abaecin、Apidaecin、Hex110、Dicer、Vhdl基因表达水平显著上调，而意蜂幼虫体内仅有Hymenoptaecin、Ago1基因表达显著上调，同时Abaecin、Apidaecin、Vg、Vhdl基因表达量显著下降。在7日龄时，中蜂幼虫体内的Hex110、Dis3、Ago1基因表达量显著下降，而意蜂幼虫体内的Ilp1、Dicer、Co-1-iv基因表达水平显著下降。【结论】中蜂和意蜂在幼虫期都能受到SBV侵染，但中蜂的敏感度显著高于意蜂；中蜂与意蜂感染SBV后在免疫及生长发育相关基因的表达水平存在显著差异，可能与不同蜂种对病虫害的防御机制、机体的调控营养代谢及病毒引起的siRNA反应差异有关。

Abstract:

[Objective] To investigate the effects of sacbrood virus (SBV) infection on the genes associated with the immunity, metabolism, resistance to virus, and cell growth and metabolism of Apis cerana cerana and Apis mellifera ligustica. [Methods] The 2-day-old larvae were collected from the colonies of A. c. cerana and A. m. ligustica and reared in an incubator at 34 ℃ and RH 85%. The larvae were infected with SBV at 3 days old, and the dead larvae were then recorded every day. Real-time quantitative polymerase chain reaction (RT-qPCR) was employed to measure the expression levels of gene SBV, as well as the genes associated with immunity (Apidaecin, Abaecin, Hymenoptaecin, Defensin, Lys-1, Pgrp-lc, Kenny, and Domeless), metabolism (Ilp1, Hex110, and Vg), resistance to viruses (Dis3, Dicer, and Ago1), and cell development and metabolism (Vhdl, Co-1-iv, and Mta1), in the 4- and 7-day-old larvae. [Results] After infection with SBV at the same dose, all the larvae of A. c. cerana died at 8 days old, while some larvae of A. m. ligustica emerged. The relative expression of SBV in A. c. cerana was significantly higher than that in A. m. ligustica of the same days old. Compared with the control group, SBV infection significantly up-regulated the expression of Abaecin, Apidaecin, Hex110, Dicer, and Vhdl in the 4-day old larvae of A. c. cerana, and it up-regulated the expression of Hymenoptaecin and Ago1 and down-regulated that of Apidaecin, Abaecin, Vg, and Vhdl in the 4-day-old larvae of A. m. ligustica. In addition, SBV infection down-regulated the expression levels of Hex110, Dis3, and Ago1 in the 7-day-old larvae of A. c. cerana and Ilp1, Dicer, and Co-1-iv in the 7-day-old larvae of A. m. ligustica. [Conclusion] The larvae of A. c. cerana were more susceptible to SBV infection than those of A. m. ligustica. The significant differences in the expression levels of the genes involved in immunity and development between A. c. cerana and A. m. ligustica may be associated with the differences in the defense mechanism against diseases and pests, the regulation of nutrient metabolism, and the virus-caused siRNA response.