Volume 27, Issue 6 p. 824-834
Original Article

The terpenoid backbone biosynthesis pathway directly affects the biosynthesis of alarm pheromone in the aphid

Z.-J. Sun

Z.-J. Sun

Department of Entomology, MOA Key Laboratory for Monitoring and Environment-Friendly Control of Crop Pests, College of Plant Protection, China Agricultural University, Beijing, China

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Z.-X. Li

Corresponding Author

Z.-X. Li

Department of Entomology, MOA Key Laboratory for Monitoring and Environment-Friendly Control of Crop Pests, College of Plant Protection, China Agricultural University, Beijing, China

Correspondence: Professor Zheng-Xi Li, Department of Entomology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, China; e-mail: [email protected]

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First published: 24 July 2018
Citations: 15

Abstract

The terpenoid backbone biosynthesis pathway is responsible for the synthesis of different backbones for terpenoids; (E)-β-farnesene (EβF), a sesquiterpene, is the major component of aphid alarm pheromone. Our previous studies eliminated the possibility of host plants and endosymbionts as the sources of EβF, and we thus speculate that the terpenoid pathway might affect the biosynthesis of EβF in aphids. First, the transcriptional responses of four genes encoding farnesyl diphosphate synthase (FPPS), geranylgeranyl diphosphate synthase (GGPPS) and decaprenyl diphosphate synthase in the cotton aphid Aphis gossypii to simulated stimulation were analysed using quantitative real-time PCR, showing an immediate decrease in the transcript abundances of the four genes. Next, RNA-interference-mediated gene knockdown was performed, indicating that fpps knockdown caused a significant cost in terms of body size and fecundity. Finally, an association analysis of gene knockdown with the amount of EβF was conducted, revealing that the concentration of EβF per milligram of aphid was drastically decreased in response to fpps knockdown, whereas ggpps knockdown significantly raised the concentration of EβF. Our data support a peculiar mode of biosynthesis and storage of the aphid alarm pheromone that relies directly on the terpenoid backbone biosynthesis pathway in the aphid.