Ecdysone signaling underlies the pea aphid transgenerational wing polyphenism

Abstract

The wing polyphenism of pea aphids is a compelling laboratory model with which to study the molecular mechanisms underlying phenotypic plasticity. In this polyphenism, environmental stressors such as high aphid density cause asexual, viviparous adult female aphids to alter the developmental fate of their embryos from wingless to winged morphs. This polyphenism is transgenerational, in that the pea aphid mother experiences the environmental signals, but it is her offspring that are affected. Previous research suggested that the steroid hormone ecdysone may play a role in this polyphenism. Here, we analyzed ecdysone-related gene expression patterns and found that they were consistent with a down-regulation of the ecdysone pathway being involved in the production of winged offspring. We therefore predicted that reduced ecdysone signaling would result in more winged offspring. Experimental injections of ecdysone or its analog resulted in a decreased production of winged offspring. Conversely, interfering with ecdysone signaling using an ecdysone receptor antagonist or knocking down the ecdysone receptor gene with RNAi resulted in an increased production of winged offspring. Our results are therefore consistent with the idea that ecdysone plays a causative role in the regulation of the proportion of winged offspring produced in response to crowding in this polyphenism. Our results also show that an environmentally regulated maternal hormone can mediate phenotype production in the next generation, as well as provide significant insight into the molecular mechanisms underlying the functioning of transgenerational phenotypic plasticity.

Silencing cathepsin L expression reduces Myzus persicae protein content and the nutritional value as prey for Coccinella septempunctata

“…Therefore, given the level of sequence divergence between the corresponding M. persicae genes and the Be. tabaci ecdysone receptor and P. solenopsis chitin synthase constructs (Table S1), the RNAi effects on the expression levels of these genes are likely to be more minor than those observed with M. persicae cathepsin L. Moreover, we did not observe the morphological phenotypes that were previously reported when silencing ecdysone receptor or chitin synthase expression (Zhu et al , ; Khan et al , ; Shang et al , ; Yan et al , ; Vellichirammal et al , ; Zhao et al , ), and the identified protein accumulation deficit is more similar to what one would expect from silencing the expression of a gut protease.…”

“…Based on what is known about the RNAi, four mismatches in the centre of a sequence should eliminate expression silencing. RNAi of ecdysone receptor expression resulted in moulting defects in several insect species and, in particular, caused more frequent wing formation in aphids (Zhu et al , ; Yan et al , ; Vellichirammal et al , ). We did not observe such a phenotype in our M. persicae experiments.…”

Plant‐mediated gene silencing of an essential olfactory‐related Gqα gene enhances resistance to grain aphid in common wheat in greenhouse and field

“…This method leads to considerable environmental pollution and health hazards for farmers, as well as significantly increasing the costs of wheat production. Now a plant‐mediated RNA interference (RNAi) strategy has been shown to be effective for the development of aphid‐resistant germplasm or cultivars . However, we found no published reports of using a gene involved in olfactory perception to control wheat aphid in field.…”

“…Now a plant-mediated RNA interference (RNAi) strategy has been shown to be effective for the development of aphid-resistant germplasm or cultivars. [5][6][7][8] However, we found no published reports of using a gene involved in olfactory perception to control wheat aphid in field.…”

Transcriptome profiling of maternal stress‐induced wing dimorphism in pea aphids

“…The result partly confirmed the role of octopamine in the regulation of wing dimorphism in the pea aphids. A subsequent study demonstrated that ecdysone signaling pathway is also involved in the transgenerational wing determination (Vellichirammal, Gupta, Hall, & Brisson, ). Females injected with ecdysone or its analog produced more winged offspring.…”