The variegated cutworm Peridroma saucia (Hübner) is a worldwide pest that causes serious damage to many crops. To recognize sex pheromones and host plant volatiles, insects depend on olfactory chemoreception involving general odorant-binding proteins (GOBPs). In this study, PsauGOBP1 was cloned from the adult antennae of P. saucia. RT-qPCR and Western-blot analysis showed that PsauGOBP1 was specifically and equally expressed in the adult antennae of both females and males. Fluorescence competitive-binding assays with sex pheromones and host plant volatiles demonstrated that PsauGOBP1 bound to six host plant volatiles: (Z)-3-hexenyl acetate (KD = 4.0 ± 0.1 μM), citral (KD = 5.6 ± 0.4 μM), farnesol (KD = 6.4 ± 0.6 μM), nonanal (KD = 6.8 ± 0.3 μM), (Z)-3-hexen-1-ol (KD = 8.5 ± 0.6 μM), and benzaldehyde (KD = 9.4 ± 0.5 μM). Electroantennogram recordings with the six host plant volatiles indicated that (Z)-3-hexenyl acetate elicited the strongest responses from both male and female antennae. Further bioassays using Y-tube olfactometers showed that (Z)-3-hexenyl acetate was attractive to adult P. saucia of both sexes. These results suggest that PsauGOBP1 might be involved in detecting host plant volatiles and that (Z)-3-hexenyl acetate might serve as a potential attractant for the biological control of P. saucia.
Keywords: EAG recording; Peridroma saucia; Western blot; behavioral response; fluorescence competitive binding; general odorant-binding protein; real-time quantitative PCR.