🦠 Classification of Prokaryotic Pathogens
Classification and major groups of prokaryotic plant pathogens including bacteria and mollicutes.
Prokaryotic pathogens are critical in plant disease diagnosis because many vascular and systemic disorders are caused by bacterial and mollicute groups.
Major Prokaryotic Groups in Plant Pathology
Key groups include:
- True bacteria.
- Fastidious vascular bacteria (RLB group in classical teaching).
- Phytoplasmas.
- Spiroplasmas.
True Bacteria
Features:
- Rigid cell wall, binary fission.
- Usually rod-shaped in plant pathology.
- Cause cankers, blights, wilts, soft rots, and galls.
Fastidious Vascular Bacteria
Characteristics:
- Difficult to culture.
- Often xylem- or phloem-limited.
- Spread through insect vectors and grafting.
Phytoplasmas and Spiroplasmas
Both are wall-less mollicutes, but differ morphologically.
- Phytoplasmas: pleomorphic, phloem-limited.
- Spiroplasmas: helical and motile.
Common symptoms include little leaf, phyllody, yellows, and stunting.
Diagnostic and Management Notes
Practical diagnosis uses symptomatology, vector relation, microscopy, and molecular assays. Management emphasizes vector control, healthy planting material, and removal of infected reservoirs.
Summary Cheat Sheet
| Group | Key Feature | Typical Symptom Pattern |
|---|---|---|
| True bacteria | Cell wall present | Canker, blight, wilt |
| Fastidious bacteria | Vascular-limited, hard to culture | Chronic decline, scorch |
| Phytoplasma | Wall-less, phloem-limited | Little leaf, phyllody |
| Spiroplasma | Helical mollicute | Stunting, chlorosis |
References
1 source • [1]
References
Used for: Foundational bacterial and mollicute classification used in crop disease education.
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