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Cucumber-mosaic-virus-associated RNA-5. XII. Symptom-modulating effect is codetermined by the helper virus satellite
J M Kaper1, M E Tousignant, L M Geletka
1Microbiology and Plant Pathology Laboratory, US Department of Agriculture, Beltsville, MD 20705.
Research in Virology
|September 1, 1990
Summary
Cucumber mosaic virus (CMV) satellite RNA-5 (CARNA-5) causes lethal necrosis or stunting in tomato, depending on the helper virus strain. This highlights the crucial role of helper virus interactions in modulating CARNA-5 disease effects.
Area of Science:
- Plant Virology
- Molecular Plant Pathology
- RNA Virus Research
Background:
- Cucumber mosaic virus (CMV) is a significant plant pathogen affecting numerous crops worldwide.
- Satellite RNAs (CARNA-5) are RNA molecules dependent on a helper virus for replication and can modulate disease symptoms.
- The disease-causing potential of CARNA-5 in tomato is known, but its interaction with different helper virus strains requires further investigation.
Purpose of the Study:
- To investigate the disease-modulating effects of a specific CMV satellite RNA (T-CARNA-5) in tomato when coinfected with different CMV helper virus strains.
- To determine the influence of helper virus strains on the replication and biological expression of T-CARNA-5.
- To establish a direct relationship between T-CARNA-5 and observed tomato disease symptoms.
Main Methods:
- Infection of tomato plants with different CMV strains and T-CARNA-5 or a non-necrogenic control (S-CARNA-5).
- Dilution endpoint bioassays to assess the infectivity and pathogenicity of T-CARNA-5.
- Total nucleic acid extraction and analysis to detect and quantify viral RNA, ssCARNA-5, and dsCARNA-5.
Main Results:
- T-CARNA-5 induced lethal necrosis with two CMV strains but aggravated stunting with a third strain (CMV-Ix).
- The primary sequence of T-CARNA-5 remained conserved across different helper virus infections.
- Viral RNA, ssCARNA-5, and dsCARNA-5 were detected in varying proportions, with ss- and dsCARNA-5 absent in one specific CMV-Ix/S-CARNA-5 combination.
Conclusions:
- The disease symptoms induced by T-CARNA-5 in tomato are critically dependent on the coinfecting helper virus strain.
- Helper virus strains influence CARNA-5 replication and its subsequent biological expression, leading to differential symptom modulation.
- Understanding helper virus-satellite RNA interactions is essential for predicting and managing CMV-induced diseases in tomato.