C‐type lectins (CTLs) are a superfamily of proteins found in almost all vertebrates and invertebrates. They play an important role in innate immune defences, development and epidermal structure. Here, a CTL with one carbohydrate‐recognition domain containing a highly conserved Gln‐Pro‐Asp (QPD) motif was identified in Tribolium castaneum and given the name TcCTL5. Spatiotemporal analyses showed that Tcctl5 was highly expressed in the late pupa stage and mainly existed in the central nervous system and haemolymph. The transcript level of Tcctl5 was prominently induced after bacterial infection. Recombinant TcCTL5 proteins (rTcCTL5) were found to bind to lipopolysaccharide, peptidoglycan and tested bacteria and induce microbial agglutination in the presence of Ca²⁺. Interestingly, when Tcctl5 was knocked down, the transcript level of antimicrobial peptides (AMPs) (attacin1, defensins3, coleoptericin1 and cecropins3) was prominently downregulated after induction with Gram‐negative Escherichia coli. More interestingly, Tcctl5 was knocked down, leading to increased mortality and loss of locomotor activity, which exhibited less travel distances among early adults. These results demonstrate that Tcctl5 plays an important role in the innate immune reaction and the movement of T. castaneum. Thus, it may represent an alternative molecular target for pest control and thus reduce the use of pesticides in agricultural production.

中文翻译：

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具有单一碳水化合物识别域的 C 型凝集素在红面甲虫 Tribolium castaneum 的先天免疫和运动中的作用

C 型凝集素 (CTL) 是在几乎所有脊椎动物和无脊椎动物中发现的蛋白质超家族。它们在先天免疫防御、发育和表皮结构中发挥重要作用。在这里，在Tribolium castaneum中鉴定了一个具有一个碳水化合物识别域的 CTL，该域包含一个高度保守的 Gln-Pro-Asp (QPD) 基序，并命名为 TcCTL5。时空分析表明，Tcctl5在蛹后期高表达，主要存在于中枢神经系统和血淋巴中。Tcctl5的转录水平细菌感染后明显诱导。发现重组 TcCTL5 蛋白 (rTcCTL5) 与脂多糖、肽聚糖和测试细菌结合，并在 Ca ²⁺存在下诱导微生物凝集。有趣的是，当Tcctl5被敲低时，抗菌肽 (AMP)（attacin1、防御素 3、鞘翅目菌素 1和天蚕素 3）的转录水平在革兰氏阴性大肠杆菌诱导后显着下调。更有趣的是，Tcctl5被击倒，导致死亡率增加和运动能力丧失，这在早期成人中表现出更短的旅行距离。这些结果表明Tcctl5在先天免疫反应和T. castaneum的运动中起重要作用。因此，它可能代表了害虫控制的替代分子目标，从而减少了农业生产中农药的使用。