Ma Bing, Wang Xinghong, Liu Qianxia, Zhao Yue, Su Zhiping, Chen Yujia, Hou Youming, Shi Zhanghong
State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centerfor Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centerfor Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
Dev Comp Immunol. 2023 Jul;144:104705. doi: 10.1016/j.dci.2023.104705. Epub 2023 Apr 3.
Red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, is a tremendously destructive insect pest of palm trees worldwide. Although some biological agents have been used to fight against RPW larvae, the control efficiency is still dissatisfactory. This study aimed to determine the role of a peptidoglycan recognition protein (PGRP), RfPGRP-S3, in RPW immunity. RfPGRP-S3 is a secreted protein with a DF (Asp-Phe) motif, implying that it can discriminate Gram-positive bacteria. The abundance of RfPGRP-S3 transcripts in the hemolymph was significantly higher than that in other tissues. The expression of RfPGRP-S3 can be markedly induced by challenge with Staphylococcus aureus and Beauveria bassiana. After RfPGRP-S3 was silenced, the ability of individuals to clear the pathogenic bacteria in the body cavity and gut was significantly compromised. Furthermore, silencing RfPGRP-S3 dramatically impaired the survival rate of RPW larvae upon challenge with S. aureus. RT‒qPCR revealed that the expression levels of RfDefensin in the fat body and gut were decreased by RfPGRP-S3 silencing. Taken together, these results demonstrated that RfPGRP-S3 acts as a circulating receptor to promote the expression of the antimicrobial peptide gene upon the discrimination of pathogenic microbes.
红棕象甲（RPW），即锈色棕榈象（Rhynchophorus ferrugineus Olivier），是一种对全球棕榈树极具破坏性的害虫。尽管已使用一些生物制剂来对抗红棕象甲幼虫，但防治效率仍不尽人意。本研究旨在确定一种肽聚糖识别蛋白（PGRP），即RfPGRP-S3，在红棕象甲免疫中的作用。RfPGRP-S3是一种具有DF（天冬氨酸-苯丙氨酸）基序的分泌蛋白，这意味着它可以区分革兰氏阳性菌。血淋巴中RfPGRP-S3转录本的丰度显著高于其他组织。金黄色葡萄球菌和球孢白僵菌的刺激可显著诱导RfPGRP-S3的表达。RfPGRP-S3沉默后，个体清除体腔和肠道中病原菌的能力显著受损。此外，沉默RfPGRP-S3显著降低了红棕象甲幼虫在受到金黄色葡萄球菌攻击后的存活率。RT-qPCR显示，RfPGRP-S3沉默后，脂肪体和肠道中RfDefensin的表达水平降低。综上所述，这些结果表明，RfPGRP-S3作为一种循环受体，在识别病原微生物后促进抗菌肽基因的表达。
