Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression.
Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression.
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DOI：
10.3390/toxins8020052
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发表时间：
2016-02-20
期刊：
影响因子：
4.2
通讯作者：
Ye GY
中科院分区：
文献类型：
--
作者：
Fang Q;Wang BB;Ye XH;Wang F;Ye GY
昆虫宿主/拟寄生物相互作用是共同进化的系统，其中宿主防御通过拟寄生物机制来平衡，以禁用或隐藏宿主免疫效应器。在这里，我们报道了翼手龙毒液损害了其宿主菜青虫的抗菌活性。抑制区结果表明，珠注射诱导了宿主血淋巴的抗菌活性，但毒液却抑制了它。筛选了编码天蚕素和溶菌酶的cDNA。相对定量 PCR 结果表明，所有微生物和珠注射均上调了这两个基因的转录水平，但毒液却下调了它们。在珠子攻击后8小时，天蚕素基因的转录水平出现峰值，而溶菌酶基因的峰值出现在24小时。这两个基因的转录水平在粒细胞和脂肪体中高于其他组织。 RNA干扰降低了这两个基因的转录水平和蛹血淋巴的抗菌活性。同样，在治疗后的前 8 小时内，毒液注射以时间和剂量依赖性方式沉默了这两个基因的表达，此后沉默效果减弱。另外，重组天蚕素和溶菌酶对雌性蛹寄生的蛹羽化率没有显着影响。这些发现表明寄生蜂毒液损害宿主抗菌活性的一种机制。
Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom.