Partial elimination ofWolbachiain the Asian citrus psyllid,Diaphorina citri, increases phytopathogen acquisition and decreases fitness

Abstract

AbstractWolbachiais a maternally inherited intracellular bacterium that infects a wide range of arthropods.Wolbachiacan have a significant impact on host biology and development, often due to its effects on reproduction. We investigatedWolbachiainfection in the Asian citrus psyllid,Diaphorina citri, which transmitsCandidatusLiberibacter asiaticus (CLas), the causal agent of citrus greening disease.D. citriare naturally infected withWolbachia; therefore, investigatingWolbachia-mediated effects onD. citrifitness andCLas transmission required artificial elimination of this endosymbiont with application of doxycycline. Doxycycline treatment of psyllids reducedWolbachiainfection by approximately 60% in both male and femaleD. citri; however, this reduction varied between generations of treated psyllids. Psyllids treated with doxycycline exhibited higherCLas acquisition as both adults and nymphs as compared with negative controls. In addition, doxycycline-treated psyllids exhibited decreased fitness as measured by reduced egg and nymph production as well as adult emergence as compared with controls lines whereWolbachiawas not manipulated. Our results indicate thatWolbachiabenefitsD. citriby improving fitness and potentially competes withCLas by interfering with phytopathogen acquisition. Targeted manipulation of endosymbionts in this phytopathogen vector may yield disease management tools.Importance of the studyThis study provides insights into the critical role ofWolbachiain the Asian citrus psyllid,Diaphorina citri, a known vector of the presumed causal agent of citrus greening disease. Our data indicate a beneficial role ofWolbachiainD. citri, whereby the bacteria greatly enhance overall fitness and affect sex ratio of the host but interfere with acquisition of the phytopathogen,CandidatusLiberibacter asiaticus (CLas). By artificially eliminatingWolbachiafrom psyllids, the study confirms its endosymbiotic role and opens potential avenues for development of disease control methods. Specifically, our data suggest that targeted manipulation of insect endosymbionts likeWolbachiamay potentially contribute new tools for management of this economically devastating and globally widespread disease of citrus.