Pectobacterium atrosepticum

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Blackleg of Potato Stem Wilt

Pectobacterium atrosepticum is a species of bacterium in the family Pectobacteriaceae. It is a plant pathogen known for causing blackleg and tuber soft rot in potatoes. This bacterium is a significant concern in agriculture due to its impact on crop yield and quality.

Taxonomy and Classification

Pectobacterium atrosepticum belongs to the domain Bacteria, phylum Proteobacteria, class Gammaproteobacteria, order Enterobacterales, and family Pectobacteriaceae. It was previously classified under the genus Erwinia but was reclassified based on molecular phylogenetics.

Morphology and Physiology

Pectobacterium atrosepticum is a Gram-negative rod-shaped bacterium. It is facultatively anaerobic, meaning it can grow in both the presence and absence of oxygen. The bacterium is motile due to the presence of peritrichous flagella.

Pathogenicity

Pectobacterium atrosepticum is a pathogen primarily affecting potato plants. It causes blackleg disease, characterized by blackening and rotting of the stem base, and tuber soft rot, which leads to the decay of potato tubers. The bacterium produces pectolytic enzymes that degrade plant cell walls, facilitating the spread of infection.

Symptoms

The symptoms of infection by Pectobacterium atrosepticum include:

• Blackening of the stem base (blackleg)
• Soft, watery rot of tubers (soft rot)
• Foul odor due to the breakdown of plant tissues

Transmission and Spread

Pectobacterium atrosepticum is spread through contaminated soil, water, and plant material. It can enter plants through wounds or natural openings. The bacterium thrives in wet and warm conditions, which facilitate its spread and infection.

Control and Management

Managing Pectobacterium atrosepticum involves several strategies:

• Use of disease-resistant potato varieties
• Proper crop rotation to reduce soil inoculum
• Sanitation practices to prevent the spread of the bacterium
• Avoiding over-irrigation and ensuring proper drainage

Research and Development

Ongoing research aims to better understand the genomics and pathogenesis of Pectobacterium atrosepticum to develop more effective control measures. Studies focus on the bacterium's virulence factors, host-pathogen interactions, and potential biocontrol agents.

See Also

• Pectobacterium
• Blackleg
• Soft rot
• Potato diseases