Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 5/4/2009
Publication Date: 8/1/2009
Citation: Wen, A., Mallik, I., Pasche, J.S., Wang, X., Li, W., Levy, L., Lin, H., Alvarado, V.Y., Scholthof, H., Mirkov, E., Rush, C.M., Gudmestad, N.C. 2009. Incidence, Distribution, and Genetic Variations of ‘Candidatus Liberibacter sp.' Associated with Zebra Chip of Potato in North America. Phytopathology(99):S140. Interpretive Summary:
Technical Abstract: The presence of ‘Candidatus Liberibacter solanacearum’ (CLs) and ‘Candidatus Liberibacter psyllaurous’ (CLp) were confirmed in potato plants affected with zebra chip/zebra complex (ZC) disease throughout Texas potato production areas in 2005-2008, in seed tubers produced from Wyoming in 2007, and in Colorado, Kansas, Nebraska and Mexico potato production areas in 2008 using CLp/CLs specific primers in PCR assays. The PCR assays were capable of detecting 0.19 to 1.56 ng of total DNA per reaction, depending on the primer set used. The overall efficiency associated with the detection of true positives was generally less than 60%. Detection efficiencies were much higher for below ground portions of plants, such as stolons and tubers, as opposed to leaves, leaf petioles and above ground stems. The ‘Candidatus Liberibacter’ species detected in all samples divided into two clusters sharing similarity of 99.8 % in their partial 16S rDNA sequences and 99.3 % in their partial ISR-23S rDNA sequences. Genetic variations in the 16S rDNA region consistently matched with those of the ISR-23S rDNA region. In this partial 16S-ISR-23S rDNA region, there were 8 SNPs among the CLp/CLs ‘isolates’ investigated in this study. Preliminary studies suggest silverleaf nightshade (Solanum elaeagnifolium Cav.), wolfberry (Lycium barbarum L.), black nightshade (S. ptychanthum Dun.), and jalapeno pepper (Capsicum annuum L.) as potential reservoir hosts for the ZC bacterium.