Submitted to: Phytopathology
Publication Type: Literature Review
Publication Acceptance Date: 12/17/2012
Publication Date: 5/22/2013
Citation: Lin, H., Gudmestad, N.C. 2013. Aspects of pathogen genomics, diversity, epidemiology, vector dynamics and disease management for a newly emerged disease of potato: Zebra Chip. Phytopathology. 103(6):524-537. Interpretive Summary: Zebra chip (ZC) disease has caused millions of dollars in losses to the US potato industry. “Candidatus Liberibacter solanacearum” (Lso) is a bacterium associated with ZC. In this article, an overview is provided for history, biology, genomics, genetics and epidemiology of ZC disease of potatoes. As the bacterium has not been cultured, information regarding the general biology, physiology and pathogenicity of Lso is limited. Nevertheless, a great deal of progress has been made in understanding ZC disease. Characterization of the Lso genome has provided insights into the genetic basis of potential virulence and metabolic capability of this organism. Since all commercial potato cultivars appear to be susceptible to ZC and current strategies of ZC control focus mostly on insect control, more research is needed to better understand vector biology, disease mechanisms, host response and epidemiology of ZC in the context of vector-pathogen-plant interactions. These research efforts will facilitate development of sustainable, effective and integrated management strategies for ZC.
Technical Abstract: An overview is provided for the aspects of history, biology, genomics, genetics and epidemiology of zebra chip (ZC), a destructive disease of potato (Solanum tuberosum L.) that represents a major threat to potato industries in the US as well as other potato production regions in the world. The disease is associated with a gram-negative, phloem-limited, insect-vectored, unculturable prokaryote: “Candidatus Liberibacter solanacearum” (Lso) that belongs to the Rhizobiaceae family of alpha-Proteobacteria. The closest cultivated relatives of Lso are members of the group of bacteria known as the alpha-2 subgroup. In spite of the fact that Koch’s postulates have not been fulfilled, a great deal of progress has been made in understanding ZC disease. Nevertheless, more research is needed to better understand vector biology, disease mechanisms, host response and epidemiology of ZC in the context of vector-pathogen-plant interactions. Current ZC management strategies focus primarily on psyllid control. The ultimate control of ZC likely relies on host resistance. Unfortunately, all currently grown commercial potato cultivars are susceptible to ZC. Elucidation of the Lso genome sequence has provided insights into the genetic basis of potential virulence and metabolic capability of this organism. Finally, effective, sustainable management of ZC is likely to be based on integrated strategies, including removal or reduction of vectors or inocula, improvement of host resistance to the presumptive pathogen and psyllid vectors, and novel gene-based therapeutic treatment.