Isolation of streptomycetes causing common scab from 3-years old potato samples from South America
¹Charles University, Faculty of Science, Department of Genetics and Microbiology,
Viničná 5, CZ-12843 Prague 2, Czech Republic
²Crop Research Institute, Laboratory of Epidemiology and Ecology of Microorganisms, Drnovská 73, 161 06 Prague, Czech Republic
³Czech University of Life Sciences, Faculty of Agrobiology, Food, and Natural
Resources, Department of Microbiology, Nutrition and Dietetics, Kamýcká 129, 165 00 Prague, Czech Republic
⁴INTA, Agricultural Experimental Station Balcarce, 7620 Balcarce, Buenos Aires,
Argentina
Abstract:
In this paper, we aimed at assessing the best conditions for the isolation of actinobacteria from old potato samples. A set of media and pretreatments were tested. The optimal were chosen for the isolation of actinobacteria from potatoes from Peru, Chile and Argentina. Isolates were tested on the presence of thaxtomin phytotoxin by amplification of the respective gene. Phylogenetic position of strains was compared with their geographical origin, pathogenic potential and existence of common scab (CS) symptoms on potato sample. We demonstrated that RNAlater can be successfully used for the long-term preservation of potato peel for subsequent isolation of actinobacteria on R2A medium. Many streptomycetes were thaxtomin-positive, though they are distantly-related to described pathogens causing CS. Genus Nocardia was first reported to be thaxtomin-positive. Potentially pathogenic strains were isolated not only from infected potato but also from those lacking CS symptoms. Some strains from scabby potatoes were thaxtomin-negative.
Key words:
common scab, potato disease, streptomycetes, thaxtomin