Horizontal Transmission of "Candidatus Liberibacter solanacearum" by Bactericera cockerelli (Hemiptera: Triozidae) on Convolvulus and Ipomoea (Solanales: Convolvulaceae)

Abstract

“Candidatus Liberibacter solanacearum” (Proteobacteria) is an important pathogen of solanaceous crops (Solanales: Solanaceae) in North America and New Zealand, and is the putative causal agent of zebra chip disease of potato. This phloem-limited pathogen is transmitted to potato and other solanaceous plants by the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae). While some plants in the Convolvulaceae (Solanales) are also known hosts for B. cockerelli, previous efforts to detect Liberibacter in Convolvulaceae have been unsuccessful. Moreover, studies to determine whether Liberibacter can be acquired from these plants by B. cockerelli are lacking. The goal of this study was to determine whether horizontal transmission of Liberibacter occurs among potato psyllids on two species of Convolvulaceae, sweet potato (Ipomoea batatas) and field bindweed (Convolvulus arvensis), which grows abundantly in potato growing regions of the United States. Results indicated that uninfected psyllids acquired Liberibacter from both I. batatas and C. arvensis if infected psyllids were present on plants concurrently with the uninfected psyllids. Uninfected psyllids did not acquire Liberibacter from plants if the infected psyllids were removed from the plants before the uninfected psyllids were allowed access. In contrast with previous reports, PCR did detect the presence of Liberibacter DNA in some plants. However, visible amplicons were faint and did not correspond with acquisition of the pathogen by uninfected psyllids. None of the plants exhibited disease symptoms. Results indicate that horizontal transmission of Liberibacter among potato psyllids can occur on Convolvulaceae, and that the association between Liberibacter and Convolvulaceae merits additional attention.

‘Candidatus Liberibacter solanacearum’ distribution and diversity in Scotland and the characterisation of novel haplotypes from Craspedolepta spp. (Psylloidea: Aphalaridae)

“…Assignment of the correct haplotype in a transmission study is necessary to understand the differences in plant-Lso interactions, psyllid-plant hosts and agricultural risk of different Lso haplotypes. This is evident for a few new findings: including a possible new haplotype which was suggested by Contreras-Rendon et al 8 by reanalysing existing Lso sequences from a previous study in which B. cockerelli was found to transmit Lso to C. arvensis and I. batatas 27 . Transmission of Lso by B. cockerelli to these plants has not been demonstrated for Lso haplotypes A and B. Additionally, an unidentified Bactericera sp.…”

“…The psyllid vector for this haplotype is currently unknown. The second haplotype H, referred to henceforth as H(Con), was first found infecting plants in the Convolvulaceae, including Convolvulus arvensis (field bindweed) and Ipomea batatas (sweet potato) 27 . H(Con) haplotype was assigned after further analysis of 16S ribosomal gene regions 8 but the full set of ribosomal genes necessary for assignment of new haplotypes has not been sequenced.…”

A comprehensive review of zebra chip disease in potato and its management through breeding for resistance/tolerance to ‘Candidatus Liberibacter solanacearum’ and its insect vector

“…Convolvulaceae). 72,84 CLso may be transmitted through potato tubers produced by infected plants (Fig. 1) 85 and in stolons produced by CLso-infected Physalis longifolia.…”

Candidatus Liberibacter solanacearum patógeno vascular de solanáceas: Diagnóstico y control

“…La transmisión de CLso por Bc es de forma vertical (Casteel, Hansen, Walling & Paine, 2012) y horizontal en camote (Ipomoea batatas) y enredadera silvestre (Convolvulus arvensis) (Torres et al, 2015), con período de incubación de hasta 24 h y tiempo de transmisión promedio de 15 min, no requiere de un hospedante silvestre para multiplicarse, como es el caso de algunos virus fitopatógenos. La edad fisiológica del vector no influye en la capacidad para transmitir la bacteria; sin embargo, con Bc las ninfas requieren menor tiempo (15 min) que los adultos (30 min) para adquirir CLso (Garzón et al, 2009), todos los estadios de Bc transmiten CLso y la transmisión vertical por las hembras adulto puede ser variable de 46.7-87.5% (Casteel, Hansen, Walling & Paine, 2012).…”