Functional characterization of two different decaprenyl diphosphate synthases in the vetch aphid Megoura viciae

Abstract

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.

Farnesyl/geranylgeranyl diphosphate synthases regulate the biosynthesis of alarm pheromone in a unique manner in the vetch aphid Megoura viciae

“…nos. AY968584.2 and MW175330) based on the transcriptome data of M. viciae (Song and Li, 2022). The open reading frame (ORF) of MvFPPS contained 1185 bp nucleotides encoding a 395 amino acid protein with a predicted molecular weight of 45.30 kDa and a theoretical pI of 6.52.…”

“…viciae (Song and Li, 2022; Table S1). PCR procedures were performed as described previously (Song and Li, 2022).…”

“…viciae (Song and Li, 2022; Table S1). PCR procedures were performed as described previously (Song and Li, 2022). The PCR cycling programme consisted of 95 C for 2 min, 35 cycles of 95 C for 10 s, 55 C for 30 s, 68 C for 1 min, and a final extension at 68 C for 7 min.…”

“…For temporal expression analysis, aphids were collected during different developmental stages (1st-4th instar nymphs and 2-day-old adult) (Sun & Li, 2019). The expression pattern of MvFPPS and MvGGPPS were evaluated by realtime quantitative PCR (RT-qPCR) on the ABI QuantStudio 6 Flex Detection system (Thermo Fisher, Carlsbad, CA, USA) according to the previously described protocol (Song and Li, 2022). The ribosomal protein L32 (RPL32) of A. pisum (GenBank accession no.…”

“…This is different from the single major AAP component (EβF) in the majority of aphid species, and thus can be used as a good reference for comparative studies. We identified one FPPS and one GGPPS by transcriptome sequencing and molecular cloning (designated as MvFPPS and MvGGPPS), and characterized two different functional decaprenyl diphosphate synthases (DPPS; long-chain prenyltransferases) in M. viciae (Song and Li, 2022). In the present study, we characterized the functions of MvFPPS and MvGGPPS by using RNA interference (RNAi) combined with gas chromatography-mass spectrometry (GC-MS), real-time quantitative polymerase chain reaction (RT-qPCR)-based spatio-temporal profiling.…”