Pest resistance function of BtACO8 gene from Balsas teosinte.

The peach aphid (Myzus persicae) is a major agricultural pest that causes significant yield losses and transmits numerous plant viruses. We profiled BtACO8 expression in Balsas teosinte and found that aphid infestation induced its transcripts 12.6-fold at 12 h post-infestation relative to non-infested controls. We therefore cloned BtACO8, encoding 1-aminocyclopropane-1-carboxylate oxidase, and investigated its role in aphid resistance by heterologous overexpression in Arabidopsis thaliana. Three homozygous BtACO8-OE lines were obtained and used for functional characterization. Compared with wild-type plants, OE lines showed higher trichome density and greater callose deposition, and supported over 50% fewer aphids, with reduced nymph hatching and reproductive capacity. Although ethylene content did not differ significantly between OE and wild-type plants, AtEIN2, a key component of ethylene signaling, was significantly upregulated in OE lines after aphid infestation. These results suggest that BtACO8 enhances aphid resistance through physical barriers and enhanced ethylene signaling, rather than through increased ethylene production. BtACO8 from Balsas teosinte is therefore a promising candidate gene for improving aphid resistance in crops.