Dickeya dadantii causes disease mainly in tropical and subtropical environments and has a wide host range, including Saintpaulia and potato. The reason for its inclusion is that D. dadantii
strain 3937 has been the Dickeya strain of choice for molecular studies for over 25 years. These studies have been instrumental in our understanding of bacterial plant pathogenesis, including
the roles of exoenzymes and sugar catabolism, iron transport, secretion and regulation, complementing related studies in other ‘soft rot erwiniae’ (including Pectobacterium carotovorum and P. atrosepticum—see next
section). Other recent areas of study include plant defence and pathogen
response to defence, pathogenesis in the pea aphid and the interaction between phytopathogens
and human pathogens on plants. The availability of a genome sequence for Dda3937, annotated through an international consortium, combined with functional genomics and systems biology
approaches, is furthering our knowledge of this and related pathogens.