Myzus persicaeSulzer aphid contains oxylipins that originate from phloem sap

Abstract

Oxylipins are oxygenated fatty acids and their derivatives that play key roles in response to stress. They are widespread in many organisms including mammals or plants but are unknown in arthropods. In this study, we identified oxylipins in Myzys persicae Sulzer aphids reared on Vicia faba L. plants. Further experiments based on: (i) Radiolabelled substrate incubation with aphid extracts, and (ii) rearing of aphids on an artificial diet revealed that aphids were unable to synthesize oxylipins. As the V. faba total leaf oxylipin profile differs from the aphid one, it was assessed whether: (i) Aphids are able to transform leaf oxylipins, or (ii) phloem sap (ingested by aphids when feeding on plants) contains oxylipins different from total leaf ones. Phloem exudates analysis revealed, for the first time, that it contains oxylipins that are different from total leaf ones. These oxylipins are further ingested by aphids.

Root-Derived Oxylipins Promote Green Peach Aphid Performance on Arabidopsis Foliage

“…Because GPAs lacks a 9-HOD synthesizing activity, it has been suggested that GPAs derive 9-HOD from the plant host (Harmel et al, 2007). Indeed, 9-HOD and other 9-LOX oxylipins are present in phloem sap (Harmel et al, 2007), and our results show that the content of 9-HOD and other 9-LOX oxylipins increases in petiole exudates collected from GPA-infested leaves compared with petiole exudates from uninfested leaves of Arabidopsis ( Figure 5A). The fact that 9-HOD added to an artificial diet resulted in an increase in size of the insect population ( Figure 5B) suggests that LOX5-synthesized oxylipins have the potential to directly affect GPA.…”

“…Some 9-LOX-derived volatiles induce oviposition in aphid predators (Verheggen et al, 2008), thus implicating a potential role for 9-LOXs in indirect defense against aphids. 9-LOXsynthesized oxylipins also accumulate both in phloem sap and in aphids feeding on plants (Harmel et al, 2007), suggesting that these oxylipins may also have a more direct role in plant-aphid interaction. Arabidopsis contains two 9-LOX-encoding genes, LOX1 (At1g55020) and LOX5 (At3g22400) (Bannenberg et al, 2009).…”

“…9-HOD is present in GPAs reared on plants, as compared with GPAs reared on an artificial diet (Harmel et al, 2007). Because GPAs lacks a 9-HOD synthesizing activity, it has been suggested that GPAs derive 9-HOD from the plant host (Harmel et al, 2007).…”

“…9-HOD is present in GPAs reared on plants, as compared with GPAs reared on an artificial diet (Harmel et al, 2007). Because GPAs lacks a 9-HOD synthesizing activity, it has been suggested that GPAs derive 9-HOD from the plant host (Harmel et al, 2007). Indeed, 9-HOD and other 9-LOX oxylipins are present in phloem sap (Harmel et al, 2007), and our results show that the content of 9-HOD and other 9-LOX oxylipins increases in petiole exudates collected from GPA-infested leaves compared with petiole exudates from uninfested leaves of Arabidopsis ( Figure 5A).…”

Organ-dependent oxylipin signature in leaves and roots of salinized tomato plants (Solanum lycopersicum)

“…Our results are compatible with a signaling role for JA in salt stress, but further experiments are required to strengthen this hypothesis. It has been shown that various oxylipins, in addition to jasmonates, can be found in the phloem revealing a potential signaling role (Harmel et al, 2007). Nevertheless, the difference between the signature of root and leaf oxylipins under salt stress does not support the hypothesis of a translocation via the phloem sap.…”