Genes important for survival or reproduction in Varroa destructor identified by RNAi

The Varroa mite,(Varroa destructor),is the worst threat to honey bee health worldwide.To explore the possibility of using RNA interference to control this pest, we determined the effects of knocking down various genes on Varroa mite survival and reproduction.Double-stranded RNA (dsRNA)of six candidate genes (Da,Pros26S,RpL8, RpL11,RpPO and RpS13)were synthesized and each injected into Varroa mites,then mite survival and reproduction were assessed.Injection of dsRNA for Da (Daughterless)and Pros26S (Gene for proteasome 26S subunit adenosine triphosphatase)caused a significant reduction in mite survival,with 3.57%±1.94% and 30.03%±11.43% mites surviving at 72 h post-inj ection (hpi),respectively.Control mites injected with green fluorescent protein (GFP)-dsRNA showed survival rates of 81.95%±5.03% and 82.36 ±2.81%,respectively. Injections of dsRNA for four other genes (RpL8,RpL11,RpPO and RpS13)did not affect survival significantly,enabling us to assess their effect on Varroa mite reproduction.The number of female offspring per mite was significantly reduced for mites injected with dsRNA of each of these four genes compared to their GFP-dsRNA controls.Knockdown of the target genes was verified by real-time polymerase chain reaction for two genes important for reproduction (RpL8,RpL11)and one gene important for survival (Pros26S). In conclusion,through RNA interference,we have discovered two genes important for mite survival and four genes important for mite reproduction.These genes could be explored as possible targets for the control of Varroa destructor in the future.

5种杀虫剂对意大利蜜蜂的急性毒性试验与安全性评价

[目的]评价5种常用杀虫剂对陆生生态的安全性。[方法]采用摄入法和触杀法测定虫螨腈、噻唑膦、氟胺氰菊酯、噻虫嗪和烯啶虫胺对意大利蜜蜂的急性毒性,并进行安全性评价。[结果]虫螨腈对意大利蜜蜂经口毒性LC_(50)(48 h)为6.13 mg a.i./L,对意大利蜜蜂接触毒性LD_(50)(48 h)为0.332μg a.i./只,均为高毒。噻唑膦对意大利蜜蜂经口毒性LC_(50)(48 h)为3.33 mg a.i./L,对意大利蜜蜂接触毒性LD_(50)(48 h)为0.828μg a.i./只,均为高毒。氟胺氰菊酯对意大利蜜蜂经口毒性LC_(50)(48 h)为202 mg a.i./L,为低毒;对意大利蜜蜂接触毒性LD_(50)(48 h)为2.64μg a.i./只,为中毒。噻虫嗪对意大利蜜蜂经口毒性LC_(50)(48 h)为0.141 mg a.i./L,为剧毒;对意大利蜜蜂接触毒性LD_(50)(48 h)为0.00709μg a.i./只,为高毒。烯啶虫胺对意大利蜜蜂经口毒性LC_(50)(48 h)为0.0951 mg a.i./L,为剧毒;对意大利蜜蜂接触毒性LD_(50)(48 h)为0.0324μg a.i./只,为高毒。[结论]上述5种杀虫剂对意大利蜜蜂的急性毒性试验均表现出不同等级的毒性,对陆生生态环境均具有潜在的生态风险。