Abstract
(E)-β-farnesene (EβF) is the major component of the alarm pheromone of many aphid species, but where EβF is synthesized in aphids is only partly understood. There are at least three most possible sources for the alarm pheromone: host plants, aphid obligate endosymbiont and aphids themselves. Here we eliminated the possibility of host plants and the obligate endosymbiont Buchnera aphidicola as the sources for EβF released by aphids. We excluded the possible effects of host plants on EβF biosynthesis by rearing aphids on non-plant diets. Both the diet-reared aphids, including the cotton aphid Aphis gossypii and the green peach aphid Myzus persicae, could still release EβF based on solid-phase micro-extraction combined with gas chromatography-mass spectrometer analysis. Meanwhile, we treated host aphids with antibiotics to fully eliminate Buchnera bacteria. Though the treatment seriously affected the development and fecundity of host aphids, the treated aphids could still release EβF, and there was no significant difference in the EβF concentration as per the aphid weight under different rearing conditions. Taken together, our experimental results suggest that host plants and obligate endosymbionts are not the sources for EβF released by aphids, indicating that it is most probably the aphid itself synthesizes the alarm pheromone.
Highlights
Aphids are among the most abundant and destructive insect pests, which damage plants by sucking phloem sap, secreting honeydew to develop plant sooty moulds, but by transmitting plant viruses[1]
Our experiments showed that the developmental duration of the first-instar M. persicae nymphs of the first generation (F1) reared on artificial diet was significantly longer than that of M. persicae reared on pepper plants (P < 0.01), while the developmental durations of the diet-reared second, third- and fourth-instar nymphs were not significantly different from those of pepper-reared ones (P = 0.198, 0.581 and 0.771, respectively) (Table 1)
We eliminated the possibility of host plants and the obligate endosymbiont Buchnera as the sources for EβF biosynthesis in two aphid species, A. gossypii and M. persicae, indicating that it is probably the aphids themselves responsible for biosynthesis of their pheromones
Summary
Aphids are among the most abundant and destructive insect pests, which damage plants by sucking phloem sap, secreting honeydew to develop plant sooty moulds, but by transmitting plant viruses[1]. FPPSs have been characterized in vitro in different aphid species[19,20,21,22,23], showing that this enzyme can utilize IPP and DMAPP to produce FPP with GPP as a transient product. Some of these EβF synthase genes have been engineered into target plants, and the latter could release EβF with an implication in aphid control[31,32,33]. The plant-originated EβF synthase was successfully used in combination with aphid FPPS to produce EβF in vitro[19], indicating that the aphid FPPS might be involved in the biosynthesis of aphid alarm pheromone. Green et al.[39] found apple α-farnesene synthase possessing prenyltransferase activity; the isoprenyl diphosphate synthase in the bark beetle Ips pini had an amateur function of terpene synthase[40, 41], while the monooxygenase albaflavenone synthase in the soil bacterium, Streptomyces coelicolor, was shown to have a moonlighting terpene synthase activity[42]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
