Ecology and genomics of Dickeya solani, a new soft rot bacterium infecting potatoes
Year: 2015
Type: dissertation
Abstract: This dissertation is aimed at studying the emergence and invasiveness of a new soft rot bacterium: Dickeya solani. Members of the Dickeya genus cause soft rot and blackleg in potato, which is one of the world s most important food crops. D. solani was first isolated in Finland in 2004; since then, it has been identified in many European countries. It most likely emerged in the Netherlands and spread elsewhere in Europe and beyond via the potato seed trade, and it has rapidly became a major threat for potato production, along with the other commonly known soft rot bacteria D. dianthicola and Pectobacterium species. In this study, the ecological aspects and genomics of D. solani were investigated to elucidate the mechanisms underlying its fast spread and high aggressiveness. A real-time PCR test was developed to analyze plant samples containing Dickeya species. This test ensures the fast determination of the amount of Dickeya cells present in symptomatic plant tissue and avoids lengthy and labored procedures for bacterial cell isolation, thereby representing an advantageous diagnostic tool. Biovar 3 Dickeya isolates were biochemically characterized and found to differ from the other known Dickeya species isolated from potatoes and ornamentals in Europe. Taxonomic analysis indicated that these strains belonged to a new species within the genus Dickeya, which was consequently named D. solani. The genome of a Finnish D. solani strain was sequenced to study the invasive character of this new species. Comparative genomic analysis indicated the presence of a set of specific genes involved in the production of toxic secondary metabolites, which triggered the investigation of the ability of D. solani to outcompete other bacterial species present in the potato environment. A newly identified bacteriocin-like molecule produced by D. solani promoted the growth inhibition of some Pectobacterium species, thus partly explaining the rapid colonization and dominance of the potato environment by this novel soft rot pathogen. This study provides novel information about the ecology, taxonomic status and genomics of the new potato pathogen D. solani. This information is likely to contribute to applied studies to improve potato production and plant health in general in the future.
Source: Työväentutkimus Vuosikirja
Author: Linda Garlant
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W1750361594