Abstract
Tomato yellow leaf curl virus (TYLCV) is a highly destructive pathogen of global tomato crops. The open reading frame (ORF) of TYLCV V2 contains two initiation codons (ATG1/V2-1 and ATG2/V2-2), producing distinct protein isoforms. Using custom antibodies, we confirmed V2-1 and V2-2 expression in infected Nicotiana benthamiana and tomato plants. Deletion mutants revealed their specialized roles: V2-1 was indispensable for viral replication and systemic spread—its loss severely reduced pathogenicity and genome accumulation. V2-2 acted as an auxiliary factor, and its deletion attenuated symptoms but kept the virus infection. Host-specific effects were observed—V2-1 deletion led to lower viral DNA/coat protein levels in N. benthamiana than in tomato, suggesting host-dependent regulation. Mutant viruses declined progressively in tomato, indicating host defense clearance. Heterologous co-expression of both isoforms via potato virus X induced systemic necrosis in N. benthamiana, demonstrating functional synergy between isoforms. Both initiation codons were essential for V2-mediated suppression of transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS). This study uncovers the mechanistic divergence of V2 isoforms in TYLCV infection, highlighting their collaborative roles in virulence and host manipulation. The findings advance understanding of geminivirus coding complexity and offer potential targets for resistance strategies.
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Claims 7
Claim · model-written summary
V2-1 and V2-2 were expressed in infected Nicotiana benthamiana and tomato.
- Taxon
- Nicotiana benthamiana and tomato plants
Solanum lycopersicum
Nicotiana benthamianae0 - Gene
- V2-1 and V2-2e0
- Outcome
- expressione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.


Verbatim
e0“we confirmed V2-1 and V2-2 expression in infected Nicotiana benthamiana and tomato plants.”
Claim · model-written summary
Loss of V2-1 severely reduced viral pathogenicity and genome accumulation.
- Taxon
- tomato
Solanum lycopersicumt0 - Treatment
- its losse0
- Gene
- V2-1e0
- Outcome
- pathogenicity and genome accumulatione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“V2-1 was indispensable for viral replication and systemic spread—its loss severely reduced pathogenicity and genome accumulation.”
t0“Tomato”
Claim · model-written summary
V2-2 deletion attenuated symptoms while infection remained.
- Taxon
- tomato
Solanum lycopersicumt0 - Treatment
- its deletione0
- Outcome
- symptomse0
- Direction
- attenuatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“its deletion attenuated symptoms but kept the virus infection.”
t0“Tomato”
Claim · model-written summary
V2-1 deletion yielded lower viral DNA and coat protein levels in N. benthamiana than tomato.
- Taxon
- N. benthamiana
Nicotiana benthamianae0 - Treatment
- V2-1 deletione0
- Gene
- V2-1e0
- Outcome
- viral DNA/coat protein levelse0
- Direction
- lowere0
- Comparator
- tomatoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“V2-1 deletion led to lower viral DNA/coat protein levels in N. benthamiana than in tomato”
Claim · model-written summary
Mutant viruses declined progressively in tomato.
- Taxon
- tomato
Solanum lycopersicume0 - Outcome
- Mutant virusese0
- Direction
- declinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Mutant viruses declined progressively in tomato”
Claim · model-written summary
Coexpression of both isoforms induced systemic necrosis in N. benthamiana.
- Taxon
- N. benthamiana
Nicotiana benthamianae0 - Treatment
- Heterologous co-expression of both isoforms via potato virus Xe0
- Outcome
- systemic necrosise0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Heterologous co-expression of both isoforms via potato virus X induced systemic necrosis in N. benthamiana”
Claim · model-written summary
Both initiation codons were necessary for V2 suppression of TGS and PTGS.
- Taxon
- tomato
Solanum lycopersicumt0 - Gene
- V2e0
- Outcome
- suppression of transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Both initiation codons were essential for V2-mediated suppression of transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS).”
t0“Tomato”