Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2008
Publication Date: 6/1/2008
Citation: Schroeder, B.K., Such, M., Sires, J.L., Porter, L., Johnson, D.A. 2008. Detection of a pathogen shift among the pectolytic bacterial pathogens of potato in Washington State. Phytopathology 98: S142.
Technical Abstract: Bacterial tuber soft rot, aerial stem rot and blackleg are significant diseases of potatoes in Washington State. These diseases are caused by Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, and Dickeya chrysanthemi, all characterized by the ability to produce pectolytic enzymes for tissue degradation. Since 2001, surveys of potato fields were conducted in the Columbia Basin of Washington state. Plants exhibiting symptoms of aerial stem rot, blackleg and tuber soft rot were obtained and bacteria were isolated. Of the 289 isolates collected, 72% were P. c. subsp. carotovorum, 11% were P. atrosepticum and 16% were D. chrysanthemi. The results for D. chrysanthemi are of considerable interest as this is a significant increase from 1% reported in the 1980s, suggesting that a pathogen shift has occurred among the soft rot bacteria in the Columbia Basin. In addition, strains of D. chrysanthemi are more aggressive than P. c. subsp. carotovorum or P. atrosepticum and exhibit a wider host range including corn. The increasing presence of D. chrysanthemi in the Columbia Basin could have long ranging effects not only on potato, but also on corn production as well.