【摘要】 【目的】调查寄生黑腹果蝇Drosophila melanogaster的日本开臂反颚茧蜂Asobara japonica的生物学特性,明确其寄生对寄主生长发育及免疫反应的影响。【方法】运用解剖成像和实时荧光定量PCR技术调查分析了日本开臂反颚茧蜂的各发育阶段发育历期、形态特征,以及日本开臂反颚茧蜂寄生黑腹果蝇2龄幼虫后的寄生率、出蜂率及寄主化蛹时间和寄主免疫通路15个主要基因(Toll通路中的SPE,Toll,Myd88,Dif和Drosomycin, Imd通路中的PGRP-LE,PGRP-LC,imd,Relish和Diptericin及PO通路中的Spn27A,MP2,yellow-f2,DoxA2和PPO1)转录水平的变化。【结果】在25±1℃,相对湿度50%±1%和光周期16L∶8D条件下,日本开臂反颚茧蜂的卵期平均为2.38±0.01 d,幼虫期为5.36±0.07 d,蛹期为8.30±0.04 d。日本开臂反颚茧蜂寄生黑腹果蝇2龄幼虫,其寄生率为94.9%±4.0%,出蜂率为64.3%±7.1%。另外,日本开臂反颚茧蜂寄生使黑腹果蝇幼虫50%化蛹时的化蛹时间比未被寄生对照显著延缓约0.5 d;寄生后黑腹果蝇抗菌肽基因Drosomycin和Diptericin转录水平显著上调,而原酚氧化酶基因PPO1转录水平则显著下调。【结论】通过延缓寄主发育和抑制寄主的黑化反应,日本开臂反颚茧蜂能够在黑腹果蝇幼虫上成功寄生。本研究的结果为进一步规模化扩繁日本开臂反颚茧蜂并进行田间生物防治应用提供了理论基础。更多还原

【Abstract】 【Aim】 This study aims to investigate the biological characteristics of the parasitoid Asobara japonica parasitizing Drosophila melanogaster and to determine the effects of its parasitization on the host growth and immune responses. 【Methods】 The developmental duration and morphological characterastics of A. japonica at different developmental stages, the parasitism rate and emergence rate of A. japonica after parasitization on the 2 nd instar larvae of D. melanogaster, the changes of host pupation time and transcriptional levels of 15 important genes of host in different immune pathways(SPE, Toll, Myd88, Dif and Drosomycin involved in Toll pathway, PGRP-LE, PGRP-LC, imd, Relish and Diptericin involved in Imd pathway and Spn27 A, MP2, yellow-f2, DoxA2 and PPO1 involved in PO pathway) in the parasitized 2 nd instar larvae of D. melanogaster were investigated and analyzed by anatomical imaging and qRT-PCR technology. 【Results】 The developmental duration of egg stage, larval stage and pupal stage of A. japonica under the conditions of 25±1℃, 50%±1% relative humidity and photoperiod of 16 L∶8 D was 2.38±0.01, 5.36±0.07 and 8.30±0.04 d, respectively. After parasitizing the 2 nd instar larvae of D. melanogaster, the parasitism rate and wasp emergence rate of A. japonica were 94.9%±4.0% and 64.3%±7.1%, respectively. Moreover, after being parasitized by A. japonica, the pupation time of D. melanogaster with 50% pupation rate was prolonged by 0.5 d, and the transcriptional levels of the antibacterial peptide genes Drosomycin and Diptericin were up-regulated significantly, whereas that of the prophenoloxidase gene PPO1 was down-regulated as compared to the unparasitized control. 【Conclusion】 A. japonica can successfully and effectively parasitize D. melanogaster larvae through triggering host developmental delay and suppressing host melanization immune responses. The results provide some useful information for the massive release programs of the agriculturally important parasitoid species A. japonica.更多还原