Abstract
Antisense-mediated gene silencing (ASGS) and posttranscriptional gene silencing (PTGS) with sense transgenes markedly reduce the steady-state mRNA levels of endogenous genes similar in transcribed sequence. RNase protection assays established that silencing in tobacco plants transformed with plant-defense-related class I sense and antisense chitinase (CHN) transgenes is at the posttranscriptional level. Infection of tobacco plants with cucumber mosaic virus strain FN and a necrotizing strain of potato virus Y, but not with potato virus X, effectively suppressed PTGS and ASGS of both the transgenes and homologous endogenes. This suggests that ASGS and PTGS share components associated with initiation and maintenance of the silent state. Small, ca. 25-nt RNAs (smRNA) of both polarities were associated with PTGS and ASGS in CHN transformants as reported for PTGS in other transgenic plants and for RNA interference in Drosophila. Similar results were obtained with an antisense class I beta-1,3-glucanase transformant showing that viral suppression and smRNAs are a more general feature of ASGS. Several current models hold that diverse signals lead to production of double-stranded RNAs, which are processed to smRNAs that then trigger PTGS. Our results provide direct evidence for mechanistic links between ASGS and PTGS and suggest that ASGS could join a common PTGS pathway at the double-stranded RNA step.
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Claims 7
Claim · model-written summary
Class I chitinase sense and antisense transgene silencing in tobacco occurs posttranscriptionally.
- Taxon
- tobacco
Nicotiana tabacume0 - Gene
- chitinase (CHN)e0
- Outcome
- silencinge0
- Qualifier
- posttranscriptional levele0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“silencing in tobacco plants transformed with plant-defense-related class I sense and antisense chitinase (CHN) transgenes is at the posttranscriptional level”
Claim · model-written summary
Cucumber mosaic virus strain FN infection suppressed PTGS and ASGS of transgenes and homologous endogenes.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- Infection of tobacco plants with cucumber mosaic virus strain FNe0
- Interactor
- cucumber mosaic virus strain FN
cucumber mosaic cucumoviruse0pathogen - Outcome
- PTGS and ASGS of both the transgenes and homologous endogenese0
- Direction
- suppressede0
- Comparator
- potato virus Xe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Infection of tobacco plants with cucumber mosaic virus strain FN and a necrotizing strain of potato virus Y, but not with potato virus X, effectively suppressed PTGS and ASGS of both the transgenes and homologous endogenes”
Claim · model-written summary
Necrotizing potato virus Y infection suppressed PTGS and ASGS of transgenes and homologous endogenes.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- a necrotizing strain of potato virus Ye0
- Interactor
- potato virus Y
Potato virus Ye0pathogen - Outcome
- PTGS and ASGS of both the transgenes and homologous endogenese0
- Direction
- suppressede0
- Comparator
- potato virus Xe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Infection of tobacco plants with cucumber mosaic virus strain FN and a necrotizing strain of potato virus Y, but not with potato virus X, effectively suppressed PTGS and ASGS of both the transgenes and homologous endogenes”
Claim · model-written summary
Potato virus X infection did not suppress PTGS or ASGS.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- potato virus Xe0
- Interactor
- potato virus XPotato virus Xe0pathogen
- Outcome
- PTGS and ASGSe0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but not with potato virus X, effectively suppressed PTGS and ASGS of both the transgenes and homologous endogenes”
t0“in tobacco”
Claim · model-written summary
Small approximately 25-nt RNAs of both polarities were associated with PTGS and ASGS in CHN transformants.
- Taxon
- tobaccoNicotiana tabacumt0
- Material
- CHN transformantse0
- Gene
- smRNAe0
- Outcome
- PTGS and ASGSe0
- Value
- ca. 25-nte0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Small, ca. 25-nt RNAs (smRNA) of both polarities were associated with PTGS and ASGS in CHN transformants”
t0“in tobacco”
Claim · model-written summary
Antisense class I beta-1,3-glucanase transformants also showed viral suppression and small RNAs.
- Taxon
- tobaccoNicotiana tabacumt0
- Material
- antisense class I beta-1,3-glucanase transformante0
- Outcome
- viral suppression and smRNAse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Similar results were obtained with an antisense class I beta-1,3-glucanase transformant showing that viral suppression and smRNAs are a more general feature of ASGS”
t0“in tobacco”
Claim · model-written summary
The authors infer a mechanistic link between ASGS and PTGS, possibly converging at the double-stranded RNA step.
- Taxon
- tobaccoNicotiana tabacumt0
- Outcome
- mechanistic links between ASGS and PTGSe0
- Qualifier
- double-stranded RNA stepe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our results provide direct evidence for mechanistic links between ASGS and PTGS and suggest that ASGS could join a common PTGS pathway at the double-stranded RNA step”
t0“in tobacco”
The same questions in other papers
Solanum tuberosum · Potato virus X · Nicotiana tabacum (tobacco)Positive and negative results
9 papers in the same direction as this paper · 3 in the opposite direction
- positive
- positive
- positive
9 papers more in this group
See all 13 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.