Pseudomonas avellanae is a Gram-negative, rod-shaped, motile, obligate aerobic bacterium belonging to the family Pseudomonadaceae and the genus Pseudomonas. It is a plant pathogenic bacterium best known as the causal agent of bacterial canker and decline of hazelnut (Corylus avellana).
Taxonomy and Classification
Based on 16S rRNA analysis, P. avellanae has been placed within the Pseudomonas syringae group (also known as the P. syringae species complex). The bacterium was originally described as Pseudomonas syringae pv. avellanae (a pathovar of Pseudomonas syringae). Following DNA-DNA hybridization studies, fatty acid methyl ester analysis, whole-cell protein profiling, and 16S rRNA sequence comparisons, it was reclassified as a distinct species in 1996 (Janse et al., 1996) and formally published as Pseudomonas avellanae in 1997. Ribotypical analysis later led to the incorporation of Pseudomonas syringae pv. theae into this species.
Pathology and Economic Impact
P. avellanae is a phytopathogen that causes bacterial canker and decline in hazelnut trees (Corylus avellana L.). The disease is of major economic concern in Mediterranean nut-growing regions, particularly in central Italy and northern Greece. The bacterium enters new hosts through natural scars in early autumn, with symptoms becoming apparent in the following spring. Symptoms include cankers on branches and stems, dieback, and overall decline of the tree.
Genomic Characteristics
The bacterium harbours a type III secretion system and an effector repertoire similar to other members of the P. syringae complex. Genomic studies, including average nucleotide identity (ANI) analysis, have been used to refine the circumscription of this species.
Type Strain
The type strain is CIP 105176 (also deposited as DSM 11809, JCM 11937, and NCPPB 3487).
Synonyms
- Pseudomonas syringae pv. avellanae Dye et al. 1980
- Pseudomonas syringae pv. theae Dye et al. 1980
