Effects of pathogen-induced plant volatiles on insect vector preference

Plant pathogens significantly reduce crop yields, posing major threats to agricultural sustainability. Many plant diseases are transmitted by insect vectors, including phloem feeders such as aphids, psyllids, and leafhoppers. Vector-borne pathogens can manipulate the behavior of their vectors by altering host plant appearance or plant-emitted volatile organic compounds (VOCs), presumably to increase vector attraction and their own proliferation. Pathogen infection can change the abundance of VOCs released by an infected host plant or alter the overall composition of volatiles blends by releasing new compounds. In this study, we investigated whether infection by Candidatus Liberibacter solanacearum (Lso)—the pathogen responsible for zebra disease in potato tubers—alters plant-emitted volatiles in potato plants (Solanum tuberosum) and host preference by its vector, the potato psyllid (Bactericera cockerelli). To do so, we collected VOCs from Lso-infected and healthy potato plants and analyzed them using Gas Chromatography-Mass Spectrometry (GC-MS). To determine if Lso-infection alters potato psyllids host preference, we conducted Y-tube bioassays with Lso-infected and healthy potato plants. We hypothesized that Lso infection will increase the abundance of VOCs and/or the production of new compounds, thereby making Lso-infected plants more attractive to psyllids. This research brings new insights into the mechanisms of zebra disease transmission, an economically important emergent disease affecting potato crops.