Abstract
Based on a full-length infectious cDNA clone, gene modifications of Tobacco necrosis virus A Chinese isolate (TNV-AC) were made by site-directed mutagenesis or nucleotide deletions for in vitro transcrip-tion of mutant viral RNAs. Mechanical inoculations of Chenopodium amaranticolor with in vitro tran-scripts, containing a single nucleic acid substitution at the presumed transcriptional start sites for the two subgenomic (sg) RNAs, showed that the sgRNA1 and sgRNA2 of TNV-AC were initiated at G2184 or G2460, respectively. Mutagenesis of the translational initiation-codons for the open-reading frame (ORF) P8 or P6 encoded by sgRNA1 indicated that each of the two genes was essential for formation of local lesions on C. amaranticolor leaves, perhaps by blocking virus cell-to-cell movement, but were not necessary for viral RNA replication in the protoplast of tobacco cell BY-2. Results of prokaryotic expression showed that the ORF coding for coat protein on TNV-AC sgRNA2 was initiatively translated by the first AUG codon at nucleotides 2612―2614. Site-directed mutation of translational start codons, and deletion of the entire coding region, showed that the intact TNV-AC coat protein was dispensable for establishment of TNV-AC infection in C. amaranticolor, otherwise the numbers of local lesions and the viral RNA accumulation level were reduced, or the time to symptom appearance significantly delayed. These results suggested that the nucleotide sequence around the translational start codon coding for TNV-AC coat protein gene may play an important role in the local symptoms. Aspects of the involve-ment of the coat protein in the TNV-AC life cycle were discussed.
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Claims 8
Claim · model-written summary
The sgRNA1 and sgRNA2 of TNV-AC were initiated at G2184 or G2460, respectively.
- Taxon
- Chenopodium amaranticolor
Chenopodium amaranticolore1 - Interactor
- TNV-ACe2pathogen
- Outcome
- were initiated at G2184 or G2460e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Mechanical inoculations of Chenopodium amaranticolor”
e2“the sgRNA1 and sgRNA2 of TNV-AC were initiated at G2184 or G2460, respectively”
Claim · model-written summary
Mutating the translation initiation codons of ORF P8 or P6 made each gene essential for local lesion formation on C. amaranticolor leaves.
- Taxon
- C. amaranticolorChenopodium amaranticolore3
- Treatment
- Mutagenesis of the translational initiation-codons for the open-reading frame (ORF) P8 or P6 encoded by sgRNA1e3
- Gene
- open-reading frame (ORF) P8 or P6e3
- Outcome
- formation of local lesionse3
- Qualifier
- perhaps by blocking virus cell-to-cell movemente3
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Mutagenesis of the translational initiation-codons for the open-reading frame (ORF) P8 or P6 encoded by sgRNA1 indicated that each of the two genes was essential for formation of local lesions on C. amaranticolor leaves, perhaps by blocking virus cell-to-cell movement”
Claim · model-written summary
The same ORF P8 or P6 mutations were not necessary for viral RNA replication in tobacco cell BY-2 protoplasts.
- Taxon
- tobacco cell BY-2e4
- Treatment
- Mutagenesis of the translational initiation-codons for the open-reading frame (ORF) P8 or P6 encoded by sgRNA1e3
- Outcome
- viral RNA replicatione4
- Qualifier
- not necessarye4
Not reportedComparatorDirection
Verbatim
e3“Mutagenesis of the translational initiation-codons for the open-reading frame (ORF) P8 or P6 encoded by sgRNA1 indicated that each of the two genes was essential for formation of local lesions on C. amaranticolor leaves, perhaps by blocking virus cell-to-cell movement”
e4“but were not necessary for viral RNA replication in the protoplast of tobacco cell BY-2”
Claim · model-written summary
The coat protein ORF on TNV-AC sgRNA2 was initiatively translated from the first AUG codon at nucleotides 2612-2614.
- Taxon
- Chenopodium amaranticolorChenopodium amaranticolore1
- Gene
- coat proteine5
- Outcome
- initiatively translatede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Mechanical inoculations of Chenopodium amaranticolor”
e5“the ORF coding for coat protein on TNV-AC sgRNA2 was initiatively translated by the first AUG codon at nucleotides 2612―2614”
Claim · model-written summary
The intact TNV-AC coat protein was dispensable for establishing TNV-AC infection in C. amaranticolor.
- Taxon
- C. amaranticolorChenopodium amaranticolore6
- Treatment
- Site-directed mutation of translational start codons, and deletion of the entire coding regione6
- Interactor
- TNV-ACe6pathogen
- Gene
- intact TNV-AC coat proteine6
- Outcome
- establishment of TNV-AC infectione6
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“Site-directed mutation of translational start codons, and deletion of the entire coding region, showed that the intact TNV-AC coat protein was dispensable for establishment of TNV-AC infection in C. amaranticolor”
Claim · model-written summary
Coat protein mutations reduced the number of local lesions and the viral RNA accumulation level in C. amaranticolor.
- Taxon
- C. amaranticolorChenopodium amaranticolore7
- Treatment
- Site-directed mutation of translational start codons, and deletion of the entire coding regione7
- Interactor
- TNV-ACe7pathogen
- Outcome
- numbers of local lesions and the viral RNA accumulation levele7
- Direction
- reducede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“Site-directed mutation of translational start codons, and deletion of the entire coding region, showed that the intact TNV-AC coat protein was dispensable for establishment of TNV-AC infection in C. amaranticolor, otherwise the numbers of local lesions and the viral RNA accumulation level were reduced, or the time to symptom appearance significantly delayed”
Claim · model-written summary
Coat protein mutations significantly delayed symptom appearance in C. amaranticolor.
- Taxon
- C. amaranticolorChenopodium amaranticolore7
- Treatment
- Site-directed mutation of translational start codons, and deletion of the entire coding regione7
- Interactor
- TNV-ACe7pathogen
- Outcome
- time to symptom appearancee7
- Direction
- delayede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“Site-directed mutation of translational start codons, and deletion of the entire coding region, showed that the intact TNV-AC coat protein was dispensable for establishment of TNV-AC infection in C. amaranticolor, otherwise the numbers of local lesions and the viral RNA accumulation level were reduced, or the time to symptom appearance significantly delayed”
Claim · model-written summary
The nucleotide sequence around the coat protein translational start codon may play an important role in local symptoms.
- Taxon
- Chenopodium amaranticolorChenopodium amaranticolore1
- Gene
- TNV-AC coat protein genee7
- Outcome
- local symptomse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Mechanical inoculations of Chenopodium amaranticolor”
e7“the nucleotide sequence around the translational start codon coding for TNV-AC coat protein gene may play an important role in the local symptoms”