Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, South Korea.
Front Immunol. 2022 Apr 5;13:875239. doi: 10.3389/fimmu.2022.875239. eCollection 2022.
Western flower thrips, , is a serious pest by directly infesting host crops. It can also give indirect damage to host crops by transmitting a plant virus called tomato spotted wilt virus. A fungal pathogen, , can infect thrips. It has been used as a biopesticide. However, little is known on the defense of thrips against this fungal pathogen. This study assessed the defense of thrips against the fungal infection with respect to immunity by analyzing immune-associated genes of in both larvae and adults. Immunity-associated genes of western flower thrips were selected from three immunity steps: nonself recognition, mediation, and immune responses. For the pathogen recognition step, dorsal switch protein 1 (DSP1) was chosen. For the immune mediation step, phospholipase A (PLA) and prostaglandin E synthase were also selected. For the step of immune responses, two phenoloxidases (PO) genes and four proPO-activating peptidase genes involved in melanization against pathogens were chosen. Dual oxidase gene involved in the production of reactive oxygen species and four antimicrobial peptide genes for executing humoral immune responses were selected. All immunity-associated genes were inducible to the fungal infection. Their expression levels were induced higher in adults than in larvae by the fungal infections. However, inhibitor treatments specific to DSP1 or PLA significantly suppressed the inducible expression of these immune-associated genes, leading to significant enhancement of fungal pathogenicity. These results suggest that immunity is essential for thrips to defend against , in which DSP1 and eicosanoids play a crucial role in eliciting immune responses.
西方花蓟马， ，是一种严重的害虫，它通过直接侵害寄主作物造成直接危害。它还可以通过传播一种叫做番茄斑萎病毒的植物病毒对寄主作物造成间接损害。一种真菌病原体， ，可以感染蓟马。它已被用作生物农药。然而，对于蓟马对这种真菌病原体的防御机制知之甚少。本研究评估了蓟马对真菌感染的防御能力，分析了幼虫和成虫中 的免疫相关基因。西方花蓟马的免疫相关基因是从三个免疫步骤中选择的：非自身识别、介导和免疫反应。对于病原体识别步骤，选择了背侧开关蛋白 1（DSP1）。对于免疫介导步骤，还选择了磷脂酶 A（PLA）和前列腺素 E 合酶。对于免疫反应步骤，选择了两种酚氧化酶（PO）基因和参与黑色素形成以抵抗病原体的四个前原酚氧化酶激活肽基因。选择了参与产生活性氧的双氧化酶基因和执行体液免疫反应的四个抗菌肽基因。所有免疫相关基因都能被真菌感染诱导。真菌感染后，这些免疫相关基因在成虫中的诱导表达水平高于幼虫。然而，针对 DSP1 或 PLA 的抑制剂处理显著抑制了这些免疫相关基因的诱导表达，导致真菌致病性显著增强。这些结果表明，免疫对于蓟马抵御 至关重要，其中 DSP1 和类二十烷酸在引发免疫反应中起着关键作用。
