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Updated: May 28, 2026
08:56
Combining Analysis of DNA in a Crude Virion Extraction with the Analysis of RNA from Infected Leaves to Discover New Virus Genomes
Published on: July 27, 2018
A plant virus evolved by acquiring multiple nonconserved genes to extend its host range.
Satyanarayana Tatineni1, Cecile J Robertson, Stephen M Garnsey
1Citrus Research and Education Center, University of Florida- Institute of Food and Agricultural Sciences, Lake Alfred, FL 33850, USA.
Summary
Citrus tristeza virus (CTV) uses nonconserved genes, including p33, p18, and p13, to infect a broad range of citrus plants. These genes enable CTV to overcome host defenses and expand its host range during evolution.
Area of Science:
- Plant virology
- Molecular biology
- Evolutionary biology
Background:
- Viral genes involved in replication are conserved, while those for host interaction and defense evasion are less conserved.
- Closteroviridae viruses encode 1-5 nonconserved open reading frames (ORFs).
- Citrus tristeza virus (CTV) has nonconserved genes (p33, p18, p13) not essential for infecting lab hosts.
Purpose of the Study:
- To investigate the role of nonconserved CTV genes (p33, p18, p13) in determining the virus's extended host range.
- To understand how specific nonconserved genes contribute to systemic infection in different citrus varieties.
Main Methods:
- Systemic infection assays of CTV in various citrus hosts (Citrus macrophylla, Mexican lime, sour orange, lemon, grapefruit, calamondin).
- Comparative analysis of gene requirements (p33, p18, p13) for CTV systemic infection across different citrus species and hybrids.
Main Results:
- The nonconserved genes p33, p18, and p13 are essential for CTV's extended host range.
- Specific genes conferred infectivity in different citrus hosts: p33 for sour orange and lemon; p33 or p18 for grapefruit; p33 or p13 for calamondin.
- In some citrus hybrids, infection was achieved with at least two of the three nonconserved genes.
Conclusions:
- CTV's expanded host range is attributed to the acquisition of multiple nonconserved genes (p33, p18, p13).
- These genes facilitate interactions with diverse hosts, enabling broader host range adaptation.
- The findings highlight the significant role of nonconserved genes in viral evolution and host-plant interactions.
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