Sterol-modified plants reduce aphid performance by limiting sterol availability

Area of Science:

• Plant-insect interactions
• Molecular biology
• Agricultural science

Background:

• Sterols are vital for eukaryotic cells, but insects must obtain them from their diet.
• Plant-derived sterols are usually converted to cholesterol for insect development.
• Previous work engineered Arabidopsis thaliana with silenced HYD1, altering sterol composition.

Purpose of the Study:

• To assess the impact of HYD1-silenced Arabidopsis on the phloem-feeding aphid Myzus persicae.
• To investigate aphid performance, feeding behavior, and sterol accumulation on modified plants.
• To explore the underlying molecular mechanisms in plants and aphids.

Main Methods:

• Evaluating aphid growth, reproduction, and survival on HYD1 RNAi lines versus wild-type.
• Conducting host choice assays and electropenetrography (EPG) to study feeding behavior.
• Analyzing sterol profiles in aphids and phloem sap using chromatography.
• Performing RNA-sequencing (RNA-seq) on HYD1 RNAi plants to examine gene expression.

Main Results:

• Aphids on HYD1 RNAi lines showed significantly reduced growth, reproduction, and survival.
• No differences in host preference or feeding behavior were observed between plant lines.
• Myzus persicae did not accumulate atypical sterols; total sterol content was reduced.
• Phloem sap sterol profiles reflected the reduced sterol content of the modified plants.
• RNA-seq revealed no activation of plant defense pathways, but upregulation of translation and nitrate metabolism genes.

Conclusions:

• HYD1 silencing in plants reduces host suitability for aphids by limiting sterol availability.
• This sterol modification strategy shows potential for managing phloem sap-feeding insect pests.
• Altering plant sterol metabolism offers a novel approach for crop protection.