Cytochrome P450scyp380c6andcyp380c9in Green Peach Aphid Facilitate Its Adaptation To Indole Glucosinolate-Mediated Plant Defense

BACKGROUND OverexpressingCIRCADIAN CLOCK ASSOCIATED1inArabidopsis thaliana(CCA1-ox) increases indole glucosinolate production and resistance to green peach aphid (Myzus persicae). Little is known of how aphids respond to this group of plant defense compounds or of the underlying molecular mechanism. Results Aphids reared onCCA1-oxfor over 40 generations (namely the CCA population) became less susceptible toCCA1-oxthan aphids maintained on the wild-type Col-0 (namely the COL population). This elevated tolerance was transgenerational as it remained for at least eight generations after the CCA population was transferred to Col-0. Intriguingly, transcriptome analysis indicated that all differential cytochrome P450 monooxygenase genes (MpCYPs), primarilyMpCYP4s,MpCYP380sandMpCYP6s, were more highly expressed in the CCA population. Application of a P450 inhibitor to the CCA population resulted in decreased aphid reproduction onCCA1-ox, which was not observed if aphids were reared on Col-0. When indole glucosinolate biosynthesis inCCA1-oxwas blocked using virus-induced gene silencing, the effect of the P450 inhibitor on the CCA population was attenuated, affirming the essential role played by MpCYPs in counteracting the defense mechanism inCCA1-oxthat is low or absent in Col-0. Furthermore, we used host-induced gene silencing to identify MpCYP380C6 and MpCYP380C9 that specifically facilitated the CCA population to cope withCCA1-mediated plant defense. Expression profiles revealed their possible contribution to the transgenerational tolerance observed in aphids. Conclusion MpCYP380C6 and MpCYP380C9 in aphids play a crucial role in mitigating indole glucosinolate-mediated plant defense, and this effect is transgenerational.