HparGR16 mediates the attraction of Holotrichia parallela larvae to the host roots via CO2 recognition.

BACKGROUND

CO2 is a crucial ecological cue that guides host-seeking behavior in soil-dwelling insects. Holotrichia parallela larvae, or grubs, cause severe agricultural and ecological damages. Whether CO2 plays a role in their host roots searching and the molecular mechanisms underlying this process remain unclear.

RESULTS

The behavioral experiments showed that CO2 plays an important role in the search of host roots. The electrophysiological recording revealed that grubs detect CO2 primarily through labial palps. We successfully cloned three gustatory receptors. Among these, only HparGR16 elicited sufficient responses in the two-electrode voltage clamp experiment. Subsequently, RNA interference with HparGR16 knockdown decreased both electrophysiological and behavioral responses to CO2, severely reducing its function in the attraction to host roots

CONCLUSION

Taken together, our study not only characterized HparGR16 as a CO2 receptor of H. parallela both in vivo and in vitro, but also provided a promising target to disrupt host-locating for novel pest management strategies in grubs. © 2026 Society of Chemical Industry.