Department of Entomology and MOA Key Laboratory for Monitoring and Environment-Friendly Control of Crop Pests, College of Plant Protection, China Agricultural University, Beijing, China.
Arch Insect Biochem Physiol. 2022 Aug;110(4):e21900. doi: 10.1002/arch.21900. Epub 2022 Apr 1.
Long-chain polyprenyl diphosphate synthases play a critical role in the formation of the prenyl side-chain of ubiquinones, but up to date, their functions have scarcely been characterized in insects. Here, we first cloned the complementary DNAs encoding the subunits of decaprenyl diphosphate synthase (DPPS) in the vetch aphid Megoura viciae, an important agricultural pest insect. The results showed that there existed three DPPS subunits, designated as MvDPPS1, MvDPPS2a, and MvDPPS2b, with an open reading frame of 1218, 1275, and 1290 bp, and a theoretical isoelectric point of 7.91, 6.63, and 9.62, respectively. The sequences of MvDPPS1s from different aphid species were nearly identical, while the sequences of MvDPPS2a and MvDPPS2b shared only moderate sequence similarity. Phylogenetic analysis clearly separated MvDPPS2a and MvDPPS2b, indicating a functional differentiation between them. Functional coexpression analysis in Escherichia coli showed that MvDPPS1 plus MvDPPS2a and MvDPPS1 plus MvDPPS2b, respectively, catalyzed the formation of the prenyl side-chain of the ubiquinone coenzyme Q10 (CoQ10). Interestingly, MvDPPS1 plus MvDPPS2b catalyzed the formation of the prenyl side-chain of a ubiquinone other than CoQ10. RNA interference-mediated knockdown of MvDPPS2a imposed no significant effect on MvDPPS2b, and vice versa, suggesting no compensatory action between them. In the end, we detected the product CoQ10 in the aphid, the first identification of CoQ10 in an insect species. Taken together, we characterized two functional DPPSs in M. viciae, one of which might be multifunctional. Our study helps to understand the functional plasticity of the terpenoid backbone biosynthesis pathway in insects.
长链聚异戊二烯二磷酸合酶在泛醌类异戊烯侧链的形成中起着关键作用，但迄今为止，它们在昆虫中的功能尚未得到充分表征。在这里，我们首次克隆了豆科蚜Megoura viciae 中脱磷酸酶二磷酸合酶（DPPS）亚基的 cDNA。豆科蚜是一种重要的农业害虫。结果表明，存在三种 DPPS 亚基，分别命名为 MvDPPS1、MvDPPS2a 和 MvDPPS2b，其开放阅读框分别为 1218、1275 和 1290bp，理论等电点分别为 7.91、6.63 和 9.62。不同蚜虫物种的 MvDPPS1 序列几乎相同，而 MvDPPS2a 和 MvDPPS2b 的序列只有中等的序列相似性。系统发育分析清楚地将 MvDPPS2a 和 MvDPPS2b 分开，表明它们在功能上存在分化。在大肠杆菌中的功能共表达分析表明，MvDPPS1 分别与 MvDPPS2a 和 MvDPPS2b 共同催化了泛醌辅酶 Q10（CoQ10）的异戊烯侧链的形成。有趣的是，MvDPPS1 与 MvDPPS2b 共同催化了除 CoQ10 以外的一种泛醌的异戊烯侧链的形成。MvDPPS2a 的 RNAi 介导敲低对 MvDPPS2b 没有显著影响，反之亦然，表明它们之间没有补偿作用。最后，我们在蚜虫中检测到 CoQ10 产物，这是首次在昆虫物种中鉴定出 CoQ10。综上所述，我们在 M. viciae 中鉴定了两种功能性 DPPS，其中一种可能具有多功能性。我们的研究有助于了解昆虫萜类骨架生物合成途径的功能可塑性。
