Growth and yield performance of Solanum tuberosum grown from seed potatoes infected with ‘Candidatus Liberibacter solanacearum’ haplotypes A and B

Authors: Swisher Grimm, Kylie; MUSTAFA, TARIQ - Washington State University; Cooper, William - Rodney; Munyaneza, Joseph - Joe

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2019
Publication Date: 1/15/2020
Citation: Swisher Grimm, K.D., Mustafa, T., Cooper, W.R., Munyaneza, J.E. 2020. Growth and yield performance of Solanum tuberosum grown from seed potatoes infected with ‘Candidatus Liberibacter solanacearum’ haplotypes A and B. Plant Disease. 104:688-693. https://doi.org/10.1094/PDIS-05-19-1125-RE.
DOI: https://doi.org/10.1094/PDIS-05-19-1125-RE

Interpretive Summary: Zebra chip disease of potato is an economically damaging disease in the United States, caused by two haplotypes (genetic variants) of the 'Candidatus Liberibacter solanacearum' bacterial pathogen, 'A' and 'B'. Researchers at USDA-ARS in Wapato and Prosser, Washington, in collaboration with a Washington State University scientist, assessed if seed potatoes infected with 'A' and 'B' haplotypes showed differences in plant emergence and daughter tuber yield compared to healthy, uninfected seed potatoes. Seed potato infected with either haplotype 'A' or 'B' showed lower rates of plant emergence, slower overall emergence, and reduced tuber yield and numbers compared to uninfected control seed potatoes. In general, haplotype 'B' infected seed affected plant emergence and daughter tuber yield more than haplotype 'A.' This study was the first to assess plant growth and tuber yield performance under field conditions in seed infected with two different haplotypes of the zebra chip pathogen, and suggests that infected seed should not be a significant concern for commercial production.

Technical Abstract: Zebra chip disease of potato (Solanum tuberosum) is associated with infection by ‘Candidatus Liberibacter solanacearum’ (Lso). Two haplotypes of Lso – A and B – occur in the United States. Lso haplotype B is more virulent than haplotype A, causing greater disease incidence, more severe symptoms, and greater loss in tuber yield. This study assessed whether tubers from infected plants generate new infected plants the following year. The effects of both Lso haplotypes A and B on tuber resprout were examined on five potato cultivars. When compared to uninfected tubers, overall plant emergence rate from Lso A- or B-infected tubers was lower, plants emerged slower, and plants generated lower daughter tuber yields in weight and quantity. Plants generally emerged poorly from Lso B-infected tubers and produced lower daughter tuber yields than Lso A-infected tubers. Regardless of Lso treatment, all daughter tubers were asymptomatic, and only 0.29% tested positive for Lso in experiments conducted over two years. This suggests that plants generated from Lso A- and Lso B-infected seed potatoes are likely not a significant source of Lso in potato fields.