POSTERS: New and emerging diseases
Identification of new ‘Candidatus Liberibacter solanacearum’ haplotypes in Solanum tuberosum and psyllid family Aphalaridae in Klamath Basin, Oregon
Kylie Swisher Grimm - USDA-ARS. David Horton- USDA-ARS, Stephen Garczynski- USDA-ARS, Brian Charlton- KBREC
In the United States, two haplotypes of ‘Candidatus Liberibacter solanacearum,’ A and B, have been shown to cause zebra chip disease symptoms in potato, Solanum tuberosum. In 2017, a single potato tuber from the Klamath Basin of Oregon showed classic zebra chip symptoms of darkened, striped vascular tissue and tested positive for ‘Ca. L. solanacearum’ by conventional polymerase chain reaction. Analysis of the 16S ribosomal RNA gene, 50S ribosomal proteins L10/L12 genes, and the outer membrane protein gene identified a new haplotype of ‘Ca. L. solanacearum,’ designated as haplotype F. Since potato psyllid is the known vector of ‘Ca. L. solanacearum’ haplotypes A and B, psyllids were collected from sticky cards placed in or near potato fields in the Klamath Basin to identify the insect vector of ‘Ca. L. solanacearum’ haplotype F. No potato psyllids were found, but psyllids of the Aphalaridae family (which likely do not develop on potato) were numerous, and a subset tested positive for ‘Ca. L. solanacearum.’ Further analysis of the 16S ribosomal RNA gene, 50S ribosomal proteins L10/L12 genes, and the outer membrane protein gene identified another new haplotype of ‘Ca. L. solanacearum’ in the Aphalaridae psyllids, designated here as haplotype G. These findings are the first reported identification of ‘Ca. L. solanacearum’ in the Klamath Basin of Oregon. Further research to explore the impact of these haplotypes on potato in this region of the Pacific Northwest is needed.