Low molecular weight inhibitors of virulence factor production by Pectobacterium atrosepticum (Pba)

This project was mostly funded by the Biotechnology and Biological Sciences Research Council (BBSRC) as an Industrial Partnership Award.  

The project involved studies of the bacterium Pectobacterium atrosepticum (Pba) which was previously known as Erwinia carotovora subspecies atroseptica (Eca). Its name was changed as a result of work to study the relatedness of different pectolytic bacteria (ie bacteria that can produce enzymes which break down pectin, a component of plant cell walls). The work leading to the reclassification of Eca was made possible as a result of the availability of DNA sequencing techniques. The same approaches lead to the reclassifying of Erwinia chrysanthemi as several different species of Dickeya.

The aim of the work was to provide a better understanding of the complex interactions which determine if Pba causes disease in potatoes. It was expected that a better understanding of the processes involved, and how they are governed at the molecular level, would facilitate the identification of new anti-rot agents.

The work has showed that colonies of Pba only produce plant cell wall degrading enzymes when they begin to run short of nutrients; and when they are present in sufficient numbers such that the production of enzymes is likely to result in disease. The process of causing disease in turn releases nutrients for the bacteria. The results have confirmed a particular signalling pathway, involved in the regulation of the production of the cell wall degrading enzymes, as a suitable target for the development of anti-rot agents. However, the identification of molecules that disrupt the pathway was not  possible within the lifetime of the project and continued beyond the end of the project.

To utilise the understanding of the genes and pathways involved in soft rot to try and develop low molecular weight compounds that block some of the important steps that allow Pectobacterium atrosepticum to cause rotting in potato tubers