同一生境条件下六个野生授粉蜂种间蜜蜂RNA病毒的传播与流行

RNA virus transmission and epidemic potential among six wild bee species from identical habitat conditions

【目的】新病原侵害是导致全球授粉蜂群数量持续下降的主要原因,加之现代养蜂业规模和范围的不断扩大,正对我国本土野生授粉蜂种健康造成严重威胁。为此在我国授粉蜂种多样性最为丰富的西双版纳地区开展蜜蜂RNA病毒病感染状况研究,以获取地区重要授粉蜂种蜜蜂RNA病毒感染状况数据,为本土授粉蜂种多样性保护提供基础数据。【方法】利用荧光定量PCR方法对野生授粉蜂种多样性最为丰富的西双版纳地区广泛分布的6个蜜蜂种(黑胸无刺蜂Tetragonulapagdeni、黄纹无刺蜂Lepidotrigona flavibasis、光足无刺蜂Tetragonula laeviceps、顶无刺蜂Lepidotrigona terminata、大蜜蜂Apis dorsata和小蜜蜂Apis florea)进行云南省最常见的5种蜜蜂RNA病毒[黑蜂王台病毒Black queen cell virus(BQCV)、慢性麻痹病毒Chronic bee paralysis virus(CBPV)、残翅病毒Deformed wing virus(DWV)、以色列麻痹病毒Israeli acute paralysis virus(IAPV)和囊状幼虫病毒Sacbrood bee virus(SBV)]定量定性分析。【结果】数据显示黑蜂王台病毒(BQCV)检出率最高,为56.7%;其次是囊状幼虫病毒(SBV)和慢性麻痹病毒(CBPV)分别为53.3%和44.4%,而残翅病毒(DWV)和以色列急性麻痹病毒(IAPV)感染率较低,分别为38.9%和25.6%;且这6种野生授粉蜂种均存在多种病毒联合感染的现象。因SBV在6个蜂种样本中均被检出,又对其进行了定量分析,数据显示小蜜蜂阳性样本的SBV拷贝量最高,大蜜蜂的SBV拷贝量最低,与两种饲养蜂种(西方蜜蜂Apis mellifera和东方蜜蜂Apis cerana)比较,西方蜜蜂样本的SBV携带量显著高于其他蜂种。在对6种野生蜂寄主SBV毒株的Lp区氨基酸序列的分析中发现6种野生蜂样本中的SBV的氨基酸序列与原寄主西方蜜蜂毒株发生程度不同的变异。其中小蜜蜂、黄纹无刺蜂、顶无刺蜂毒株变异度较大,并表现为一个相似度较大的变种毒株。【结论】实验结果表明因外来蜂种-西方蜜蜂饲养范围的不断扩大,其携带的多种蜜蜂RNA病毒已通过蜜粉食物途径传播到本地区多种主要授粉蜂种中,并表现较高的感染率,已对地区本土野生授粉蜂种的健康产生威胁。

[Aim]The spillover of new pathogens,potentially as a result of the co-occurrence of viruses in wild bees and honeybees,is a significant factor contributing to the decline in breeding bee colonies.The continuous expansion in the scale and scope of the beekeeping industry may also pose a threat to the health of wild bee pollinators in China.In this study,we conducted a survey on the infection status of bee RNA virus disease across six wild bee species in Xishuangbanna,a region of China known for its rich diversity in bee species.The data obtained from this research will enhance our understanding of RNA virus infections in wild bee species in this tropical region and aid in the protection of local pollinator species.[Methods]Five honeybee viruses,including Black queen cell virus(BQCV),Sacbrood bee virus(SBV),Chronic bee paralysis virus(CBPV),SBV,and Israel acute paralysis virus(IAPV)were investigated in six wild pollinating bee species from Xishuangbanna,including four species of stingless bees(Tetragonula pagdeni,Lepidotrigona flavibasis,Tetragonula laeviceps,Lepidotrigona terminata),and two species of honeybee(Apis dosata,Apis florea).[Results]Black queen cell virus(BQCV)was found to be the most prevalent virus(56.7%),followed by SBV(53.3%),CBPV(44.4%)SBV(38.9%),and IAPV(25.6%).Multiple virus co-infections were identified across all six bee species,with SBV detected and quantified in each.The results showed that the prevalence of SBV was highest in Apis florea and lowest in Apis dorsata.Amino acid sequence analysis of the Lp region from different SBV strains between the six bee hosts showed a high level of diversity compared to the original host(Apis mellifera)virus strain.The amino acid sequences from Apis florea,Lepidotrigona flavibasis,and Lepidotrigona terminata showed a high degree of similarity to the variant strain,which could be a novel sequence.[Conclusion]This research contributes valuable insights into the distribution of bee virus hosts,driven by the continuous expansion of the breeding range of introduced honeybee species(Apis mellifera).The emergence of new pathogens in A.mellifera could pose a threat to important local pollinators.