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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Genetic Improvement for Fruits & Vegetables Laboratory » Research » Publications at this Location » Publication #357487
Research Project: Potato and Other Solanaceous Crop Improvement and Disease Management

Location: Genetic Improvement for Fruits & Vegetables Laboratory

Title: Cultivar resistance to common scab disease of potato is dependent on the pathogen species

Author
item Clarke, Christopher
item KRAMER, CHARLES - University Of Maryland
item Kramer, Matthew

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/2019
Publication Date: 5/8/2019
Citation: Clarke, C.R., Kramer, C., Kramer, M.H. 2019. Cultivar resistance to common scab disease of potato is dependent on the pathogen species. Phytopathology. https://doi.org/10.1094/PHYTO-09-18-0368-R.
DOI: https://doi.org/10.1094/PHYTO-09-18-0368-R

Interpretive Summary: Common scab is a serious disease of potato that reduces crop yield and market quality. Disease symptoms are predominantly a result of a single toxin produced by the pathogenic agent. The current paradigm in common scab pathology is that a potato cultivar resistant to one species of the common scab pathogen should be resistant to all species. However, resistance to common scab disease identified in one breeding program is often not durable when tested in other potato breeding programs across the United States. Over 50 potato cultivars were infected with three distinct species of the common scab pathogen. The results revealed that some of the cultivars were resistant to one or multiple pathogen species. This result showcases several cultivars of potato that are expected to be resistant to the majority of common scab populations but also highlights that many potato cultivars are resistant to only specific species of the pathogen. Furthermore, these results emphasize that it is critical for extension specialists and growers to consider their local population of the common scab pathogen when determining which cultivars to plant for common scab resistance.

Technical Abstract: Common scab of potato is a severe superficial tuber disease caused by Streptomyces species that produce the phytotoxin thaxtomin. Because common scab development is highly dependent on the effects of a single toxin, thaxtomin, the current paradigm in common scab pathology is that a potato cultivar resistant to one strain of the common scab pathogen should be resistant to all strains. However, cultivar resistance to common scab disease identified in one breeding program is often not durable when tested in other potato breeding programs across the United States. We infected 55 potato cultivar populations with three distinct species of the common scab pathogen and identified cultivars that were resistant or susceptible to all three species and cultivars that have widely varying resistance dependent on the pathogen species. This result showcases several cultivars of potato that are expected to be resistant to the majority of common scab populations but also highlights that many potato cultivars are resistant to only specific species of the pathogen. Furthermore, these results highlight that it is critical for extension specialists and growers to consider their local population of the common scab pathogen when determining which cultivars to plant for common scab resistance.