Gut-binding peptides disrupt Candidatus Liberibacter asiaticus (CLas) transmission by Diaphorina citri

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera), transmits Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening disease, or Huanglongbing (HLB). Insecticidal application to reduce D. citri is the primary strategy used to reduce pathogen spread, resulting in insecticide-resistant vector populations and negative effects on non-target organisms. Alternative management strategies are needed to reduce the spread of CLas to healthy trees and prevent reinoculation of trees with existing infections. The goal of this investigation was to reduce citrus greening incidence by disrupting vector-mediated transmission of CLas. Several gut-binding peptides (GBP) have been identified that compete with CLas for attachment to the D. citri gut. Here, we examined whether GPBs could be used to disrupt CLas association with the D. citri gut, thereby impeding transmission. Immobilized droplet feeding and membrane feeding assays were used to evaluate the effect of GBPs on CLas acquisition by nymphs and adults, respectively. CLas acquisition and inoculation were lower among D. citri that fed on diets with GBP compared with control diets. Additionally, no differences in D. citri reproduction or mortality were observed among treatments. Our results suggest that gut-binding peptides may be a useful tool for blocking CLas spread by the psyllid vector.