Chloroplast-targeted (E)-β-farnesene synthase enhances (E)-β-farnesene release in transgenic rice to repel aphids and...

Aphids are one of the most damaging piercing-sucking pests in rice production, whose population outbreaks cause crop losses amounting to hundreds of millions of dollars annually worldwide. To address this challenge, it is highly imperative to develop aphid-resistant rice varieties through techniques such as genetic modification.

In this study, we successfully targeted the (E)-β-farnesene synthase (EβFS) to the chloroplast using the promoter of the rice Rubisco small subunit gene (rbcS) and its chloroplast transit peptide (ctp), which significantly enhanced the production of (E)-β-farnesene (EβF) in transgenic rice. At the seedling stage, the EβFS protein content was 17.6-fold higher in transgenic rice compared with that in the rice previously generated using the cauliflower mosaic virus 35S promoter (35S::EβFS). At the tillering stage, the EβF release rate reached 12.7 μg per plant per day in the transgenic rice. Olfactory behavioral assays demonstrated that the transgenic rice line generated in this study had significantly enhanced ability to repel bird cherry-oat aphids (Rhopalosiphum padi) ('Push' effect) and attract its natural enemy multicolored Asian lady beetles (Harmonia axyridis) ('Pull' effect) compared with the 35S::EβFS lines. In addition, the rbcS promoter can achieve specific expression of the EβFS gene in photosynthetic organs, avoiding unnecessary consumption of energy and resources associated with constitutive expression.

This Push-Pull strategy could protect rice plants from aphid infestation by controlling the aphid populations, providing an ecologically friendly and sustainable approach for integrated pest management in rice fields. © 2025 Society of Chemical Industry.