| Abstract Detail
Plant Protection Wanner, Leslie [1]. Differences in prevalence of common scab-causing Streptomyces species across the US. COMMON scab reduces potato quality and marketability in the US and worldwide. Common scab is caused by a small minority of species in the genus Streptomyces. To understand why common scab symptoms and severity vary in different regions of the USA, over 800 isolates were made from scabby potatoes from 13 northern US states. 425 isolates were probable plant pathogens based on the presence of genes encoding the phytotoxin, thaxtomin. Most isolates from Maine and the Midwestern states could be classified as the species S. scabies or S. europascabiei using species-specific PCR primers to unique regions of the 16s rRNA gene. Most also contained the Nec1and tomatinase A (TomA) genes characteristic of a pathogenicity island (PAI) that is horizontally transferred to new species, conferring the plant pathogenic phenotype. However the majority of isolates from one region in NY belonged to S. stelliscabiei, a species described in Europe; occasional isolates of S. stelliscabiei were also found in five other states. A majority of isolates from one location in ID could not be assigned to any of seven Streptomyces species, and were found to have a novel 16s rRNA gene sequence. Isolates of this new strain were found in three other states; all of these isolates were characterized by a lack of the Nec1 gene. Both Nec1 and TomA were missing in the majority of isolates from a location in North Dakota, and in a small number of isolates from other states. Isolates from western states had the greatest variation in species and markers for the PAI. These observations may help explain the variation in common scab severity seen in different regions of the USA, and work is underway to determine whether different Streptomyces species or strains cause differences in frequency or severity of common scab on selected potato varieties.
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1 - USDA-Agricultural Research Service, Vegetable Lab, 10300 Baltimore Ave., Beltsville, MD, 20705, USA
Keywords:
commom scab
Streptomyces scabies
Streptomyces scabiei
Streptomyces europascabiei
Streptomyces stelliscabiei
Solanum tuberosum
pathogenicity island.
Session: PAA03-9
Location: Hall of Ideas Room E/Monona Terrace
Date: Thursday, July 27th, 2006
Time: 11:00 AM
Abstract ID:270 |
