Understanding the biology and epidemiology of Dickeya solani : a recently emerged bacterial pathogen of potato

Abstract

Dickeya solani has emerged as a major threat to potato production in Europe and Israel. Its potential impact on the Scottish potato industry was studied with the goal to develop better control strategies. Molecular techniques were employed to understand the diversity of the D. solani and its comparison to other Dickeya spp. and to map the origin and spread of infection. Using nine housekeeping genes, a MLSA typing scheme was created and published online to facilitate its future tracking. MLSA established genetic variation between D. solani isolates and it was determined that D. solani is likely to be clonal. Due to the similarities between D. solani isolates, which was further aided with the sequencing of three full D. solani genomes, single nucleotide polymorphisms were discovered. Eight SNPs were identified and further investigated; allowing for the development of pyrosequencing assays. Two real-time PCR assays were developed to improve the diagnostics of D. solani by detecting and identifying D. solani specifically. These assays were further evaluated as part of the Euphresco II project on blackleg and soft rot disease. The spread of D. solani is likely to be through latently infected seed potatoes; therefore, the transmission of D. solani from infected seed potato to daughter tubers was studied. It has also been suggested that D. solani can survive and spread through stored tubers and the potential for D. solani to survive in plant material was assessed. The effectiveness of disinfectants commonly used in agriculture was also investigated and it was determined when used at the manufacturer’s recommended concentration, they were effective at controlling the pathogen on surfaces.