Pectobacterium

Pectobacterium is a genus of Gram-negative, motile rods in the family Pectobacteriaceae, order Enterobacterales. Members are plant pathogens that cause soft rot diseases in a wide range of crops and plant tissues. The genus was previously classified under Erwinia, but taxonomic revisions have placed these species in Pectobacterium. Notable species include P. carotovorum, P. atrosepticum, P. brasiliense, P. parmentieri, and P. versatile.

Biology and virulence factors are characteristic of the group. Pectobacterium species invade plant tissue and secrete cell-wall–degrading enzymes such as pectate lyases, polygalacturonases, and pectin lyases, often via a type II secretion system. This enzymatic activity leads to rapid tissue maceration and soft rot. Virulence is modulated by quorum sensing networks that regulate enzyme production and other factors. The bacteria can persist on plant debris and in soil and may survive on tubers and seeds.

Host range and symptoms are broad. They infect potato, carrot, onion, cabbage, lettuce, tomato and other crops. In potatoes, different species or subspecies are associated with soft rot and, for example, blackleg in the field. Symptoms include water-soaked lesions, mushy or collapsed tissue, and a foul odor, with severe losses during storage and transport.

Diagnosis and management rely on a combination of methods and practices. Laboratory identification uses selective media such as crystal violet pectate agar and molecular methods (PCR, sequencing) or serological assays. Management emphasizes sanitation and hygiene, crop rotation, use of certified seed or seed-tubers, minimizing wounding and rapid removal of infected tissue, and thorough disinfection of equipment. Chemical controls are limited, and biocontrol approaches and resistant cultivars are areas of ongoing work.

Epidemiology and impact are global. Pectobacterium species occur worldwide and are a major cause of postharvest losses in potato and other root and tuber crops, with outbreaks often linked to contaminated planting material or storage conditions.