Dickeya dadantii

Dickeya dadantii is a gram-negative, rod-shaped, motile bacterium that belongs to the Enterobacteriaceae family. It is a phytopathogen known for causing diseases in a wide range of plant hosts, notably resulting in soft rot in potatoes and other tuberous and bulb crops. This pathogen was previously classified under the genus Pectobacterium but was reassigned to the genus Dickeya based on molecular and biochemical characteristics.

Characteristics

Dickeya dadantii is characterized by its ability to degrade pectin, a polysaccharide present in the plant cell wall, through the production of pectinase enzymes. This action results in the typical soft rot symptoms observed in infected plants. The bacterium is capable of surviving in soil and water, and it can spread through these environments, infecting plants through wounds or natural openings.

Pathogenicity

The pathogenicity of Dickeya dadantii is complex and involves several virulence factors, including but not limited to, Type III secretion systems, cellulases, and proteases. These factors allow the bacterium to colonize plant tissues, evade plant defenses, and cause disease. The soft rot disease caused by Dickeya dadantii leads to significant economic losses in agriculture, affecting not only potato crops but also other important food crops such as tomatoes, cucumbers, and ornamental plants.

Management

Management of diseases caused by Dickeya dadantii involves an integrated approach. This includes the use of certified disease-free planting materials, proper sanitation practices to prevent the spread of the bacterium, and the application of chemical or biological control agents. Crop rotation and the avoidance of planting susceptible crops in infested fields are also recommended strategies to reduce the risk of disease.

Research

Ongoing research on Dickeya dadantii aims to better understand its pathogenicity mechanisms and to develop more effective control methods. This includes the study of its genetic makeup to identify potential targets for intervention, as well as the exploration of natural resistance in plants.

See Also

• Plant pathology
• Bacterial plant pathogens
• Pectinase
• Soft rot