Description
A “Tobacco Mosaic Virus” (55×90 cm) educational chart illustrates the structure, characteristics, and infection cycle of TMV, making it an essential resource for plant pathology and virology instruction.
Chart Features and Content
Size and Material: Measures 55×90 cm, printed in full color, and usually laminated or art-paper mounted for regular classroom use.
Structure of TMV:
Depicts TMV as a rigid, rod-shaped (filamentous) virus, approximately 300 nm long and 18 nm in diameter, composed of a helical protein capsid enclosing single-stranded RNA (ssRNA).
The capsid consists of 2130 identical protein subunits (capsomeres), each forming a spiral around the RNA genome (about 6395 nucleotides).
Biological and Pathological Features:
TMV primarily infects tobacco and other Solanaceae plants (e.g., tomato, potato, pepper), causing the characteristic “mosaic” mottling and discoloration of leaves, stunted growth, and yield loss.
The chart identifies mechanical transmission as the main infection route (tools, handling, plant contact), as the virus is extremely robust—surviving for years outside the host.
Symptoms are visually represented; leaf patterns, distortion, and color patches are commonly indicated.
Infection Cycle and Replication:
Shows entry via wounds, followed by viral RNA release, hijacking of plant cell machinery, and viral protein replication.
Movement proteins and plasmodesmata aid spread between plant cells; the virus migrates through the phloem to infect the whole plant.
Educational Value:
Clearly labeled diagrams explain core concepts like structure, genome, transmission, and the plant’s visible responses.
Suitable for secondary, college, or university-level plant sciences, and for agricultural extension.
This chart enables students to visually identify TMV, understand its molecular biology, and appreciate plant-virus interactions crucial for crop protection.