半闭弯尾姬蜂寄生及其毒液对小菜蛾幼虫血细胞吞噬作用的影响  

Effect of parasitism by Diadegma semiclausum(Hymenoptera:Ichneumonidae) and its venom on the phagocytic ability of hemocytes from Plutella xylostella(Lepidoptera:Plutellidae) larvae

作　　者：黄芳[1,2] 时敏[1] 陈学新[1] 章金明[2] 

机构地区：[1]浙江大学昆虫科学研究所,杭州310029 [2]浙江省农业科学院植物保护和微生物研究所,杭州310021

出　　处：《昆虫学报》2011年第9期989-996,共8页Acta Entomologica Sinica

基　　金：国家自然科学基金面上项目(30871675);国家自然科学基金创新群体项目(31021003);博士点基金(200803350092);浙江省自然科学基金重点项目(Z3100296)

摘　　要：半闭弯尾姬蜂Diadegma semiclausum是小菜蛾Plutella xylostella的优势内寄生蜂,拥有毒液、多分DNA病毒(PDV)等寄生因子,能有效调控寄主幼虫的营养生理和免疫系统,但其毒液在这过程中的功能不明。本文利用SDS-PAGE方法分析了半闭弯尾姬蜂毒液的蛋白组分,利用寄主幼虫血细胞体外原代培养的方法,研究了小菜蛾幼虫血细胞噬菌能力在半闭弯尾姬蜂寄生后的变化情况。结果表明:半闭弯尾姬蜂毒液蛋白分子量主要集中在35～220kDa之间,少数小于15kDa,但分子量处于35～70kDa之间的蛋白含量较高,与其他寄生蜂毒液蛋白相似。半闭弯尾姬蜂毒液单独对寄主小菜蛾幼虫功能血细胞(浆血细胞和颗粒血细胞)的延展能力和吞噬功能不产生破坏作用。但半闭弯尾姬蜂寄生后短时间内,寄主功能血细胞的延展受到抑制,然而功能血细胞仍然能识别外源异物,却无法进一步吞噬外源物;寄生后24h,功能血细胞的延展力恢复,颗粒血细胞的吞噬作用可顺利完成。本研究证明了半闭弯尾姬蜂寄生能暂时性地抑制颗粒血细胞的延展性从而影响其噬菌过程。Diadegma semiclausum Hellen is a larval endoparasitoid of the diamondback moth,Plutella xylostella L.The parasitoid regulates its host physiology and development mediated by its maternal secretions,such as venom and polydnavirus（PDV）,but the possible functions of venom of this PDV-producing endoparasitoid are unknown.The SDS-PAGE analysis of venom showed that the most protein bands ranged from 35 to 220 kDa with a few bands less than 15 kDa,but the most abundant bands were within 35-70 kDa,which were similar to venom proteins in other parasitoid-host systems.By in vitro primary-culture of host hemocytes with parasitoid venom fluid or Escherichia coli,the changes of spreading and phagocytic abilities of hemocytes from the parasitized or the non-parasitized host larvae indicated that the venom of D.semiclausum alone was harmless to the spreading and phagocytic abilities of plasmatocytes and granulocytes in larvae of the diamondback moth.However,the spreading ability of hemocytes from host larvae was obviously inhibited in the early stage of parasitism by D.semiclausum,but these hemocytes could still recognize the pathogens with a lapse of endocytosis;at 24 h post-parasitization,the hemocytes recovered their spreading ability and then granulocytes acted as phagocytes to engulf bacteria successfully.This study demonstrates that the parasitism of D.semiclausum can affect the phagocytosis of hemocytes from its host larvae through inhibiting the spreading ability of granulocytes.

关 键 词：半闭弯尾姬蜂 小菜蛾 寄生 毒液 多分DNA病毒 血细胞 血细胞延展 吞噬作用 

分 类 号：Q965[生物学—昆虫学]