Pseudomonas cichorii is a Gram-negative soil bacterium that is pathogenic to plants. It has a wide host range, and can have an important economical impact on lettuce, celery and chrysanthemum crops. P. cichorii was first isolated on endives (Cichorium endivia), from which it derives its name. It produces 6-aminopenicillanic acid. Based on 16S rRNA analysis, P. cichorii has been placed in the P. syringae group.