Influence of the Pathogen Candidatus Liberibacter Solanacearum on Tomato Host Plant Volatiles and Psyllid Vector Settlement

Abstract

Candidatus Liberibacter solanacearum (CLso) is an unculturable bacterium vectored by the tomato potato psyllid (TPP) Bactericera cockerelli and has been associated with Zebra chip disease in potato and with other economically relevant symptoms observed in solanaceous crops. By altering their host and vector's biological system, pathogens are able to induce changes that benefit them by increasing their transmission rate. Understanding these changes can enable better targeting of mechanisms to control pathogen outbreaks. Here, we explored how the CLso infectious status affects the volatile organic compounds (VOCs) of the tomato plant, and whether the CLso infectious status of TPP influences host plant settlement. These chemical and behavioral changes can ultimately affect the rate of encounter between the host and the vector. Results from headspace volatile collection of tomato plants showed that CLso infected tomato plants emitted a qualitatively and quantitatively different blend of VOCs compared to sham-infected plants. By a factorial experiment, we showed that CLso negative (CLso-) TPP preferred to settle 70 % more often on infected tomato plants, while CLso positive (CLso+) TPP were found 68 % more often on sham-infected tomato plants. These results provide new evidence in favor of both host and vector manipulation by CLso.

Characterization of the electrical penetration graphs of the psyllid Bactericera trigonica on carrots

“…Those changes could be advantageous, neutral, or disadvantageous for transmission. It is well‐known that changes in host plants mediated by Lso affect host preference by its vectors, which increases Lso transmission (Davis et al., ; Mas et al., ). Nevertheless, the direct effects of Lso on its vectors have received little attention, and this study proves that Lso may directly modify the stylet penetration activities of its vector, B. trigonica .…”

Chemical Communication between Phytopathogens, Their Host Plants and Vector Insects and Eavesdropping by Natural Enemies

“…It has been shown in recent years that some phytopathogens manipulate the behavior of their vectors by altering the attractiveness of the vector's host plants by increasing the amount or changing the composition of VOCs emitted by infected plants. This has been shown for pathogenic bacteria (Mayer et al, 2008a,b;Davis et al, 2012;Mann et al, 2012;Shapiro et al, 2012;Mas et al, 2014) and viruses (Eigenbrode et al, 2002;Mauck et al, 2010). Recently it was shown that the apple proliferation phytoplasma Ca.…”

The influence of bacteria on multitrophic interactions among plants, psyllids, and pathogen

“…For instance, B. cockerelli initially settled on infected potato plants, but later moved to and oviposited preferentially on plants that had been exposed to uninfected psyllids (Davis et al ., ). Interestingly, CLso‐negative B. cockerelli settled preferentially on CLso‐infected tomato plants, while CLso‐positive psyllids preferred the uninfected tomato plants (Mas et al ., ). Similarly, D. citri were more attracted to the volatile profiles of CLas‐infected sweet orange trees ( Citrus sinensis ) initially; however after feeding, psyllids preferentially dispersed to noninfected rather than infected plants, but the infectious status of the insect did not affect the psyllid behavior (Mann et al ., ).…”