Abstract
The response of tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants, epigenetically suppressed for phenylalanine ammonia‐lyase (PAL) activity, was studied following infection by tobacco mosaic virus (TMV). These plants contain a bean PAL2 transgene in the sense orientation, and have reduced endogenous tobacco PAL mRNA and suppressed production of phenylpropanoid products. Lesions induced by TMV infection of PAL‐suppressed plants are markedly different in appearance from those induced on control plants that have lost the bean transgene through segregation, with a reduced deposition of phenofics. However, they develop at the same rate as on control tobacco, and pathogenesis‐related (PR) proteins are induced normally upon primary infection. The levels of free salicylic acid (SA) produced in primary inoculated leaves of PAL‐suppressed plants are approximately fourfold lower than in control plants after 84 h, and a similar reduction is observed in systemic leaves. PR proteins are not induced in systemic leaves of PAL‐suppressed plants, and secondary infection with TMV does not result in the restriction of lesion size and number seen in control plants undergoing systemic acquired resistance (SAR). In grafting experiments between wild‐type and PAL‐suppressed tobacco, the SAR response can be transmitted from a PAL‐suppressed root‐stock, but SAR is not observed if the scion is PAL‐suppressed. This indicates that, even if SA is the systemic signal for establishment of SAR, the amount of pre‐existing phenylpropanoid compounds in systemic leaves, or the ability to synthesize further phenylpropanoids in response to the systemic signal, may be important for the establishment of SAR. Treatment of PAL‐suppressed plants with dichloro‐isonicotinic acid (INA) induces PR protein expression and SAR against subsequent TMV infection. However, treatment with SA, while inducing PR proteins, only partially restores SAR, further suggesting that de novo synthesis of SA, and/or the presence or synthesis of other phenylpropanoids, is required for expression of resistance in systemic leaves.
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Claims 13
Claim · model-written summary
Lesions on PAL-suppressed tobacco develop at the same rate as on control tobacco after TMV infection.
- Taxon
- tobacco
Nicotiana tabacume0 - Treatment
- infection by tobacco mosaic viruse1
- Outcome
- develop at the same ratee2
- Direction
- no_changeinferrede2
- Comparator
- control tobaccoe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“following infection by tobacco mosaic virus (TMV)”
e2“they develop at the same rate as on control tobacco”
Claim · model-written summary
Lesions induced by TMV on PAL-suppressed plants differ markedly in appearance from those on control plants.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- appearancee4
- Qualifier
- markedly differente4
- Comparator
- control plantse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e4“Lesions induced by TMV infection of PAL‐suppressed plants are markedly different in appearance from those induced on control plants”
Claim · model-written summary
PAL-suppressed tobacco lesions show a reduced deposition of phenolics.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- deposition of phenoficse5
- Direction
- reducede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e5“with a reduced deposition of phenofics”
Claim · model-written summary
PR proteins are induced normally in PAL-suppressed tobacco upon primary infection.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- pathogenesis‐related (PR) proteins are induced normallye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e3“pathogenesis‐related (PR) proteins are induced normally upon primary infection”
Claim · model-written summary
Free salicylic acid levels in primary inoculated leaves of PAL-suppressed tobacco are approximately fourfold lower than in control plants after 84 h.
- Taxon
- tobaccoNicotiana tabacume0
- Organ / stage
- primary inoculated leavese6
- Outcome
- levels of free salicylic acide6
- Direction
- lowere6
- Value
- approximately fourfolde6
- Comparator
- control plantse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e6“The levels of free salicylic acid (SA) produced in primary inoculated leaves of PAL‐suppressed plants are approximately fourfold lower than in control plants after 84 h”
Claim · model-written summary
PR proteins are not induced in systemic leaves of PAL-suppressed tobacco.
- Taxon
- tobaccoNicotiana tabacume0
- Organ / stage
- systemic leavese7
- Outcome
- PR proteins are not inducede7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e7“PR proteins are not induced in systemic leaves of PAL‐suppressed plants”
Claim · model-written summary
Secondary TMV infection does not restrict lesion size and number in PAL-suppressed tobacco, unlike control plants undergoing SAR.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- secondary infection with TMVe1
- Outcome
- restriction of lesion size and numbere1
- Direction
- no_changeinferrede1
- Comparator
- control plantse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“secondary infection with TMV does not result in the restriction of lesion size and number seen in control plants undergoing systemic acquired resistance (SAR)”
Claim · model-written summary
The SAR response can be transmitted from a PAL-suppressed rootstock.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- SAR response can be transmittede1
- Qualifier
- from a PAL‐suppressed root‐stocke1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“the SAR response can be transmitted from a PAL‐suppressed root‐stock”
Claim · model-written summary
SAR is not observed when the scion is PAL-suppressed.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- SAR is not observede1
- Qualifier
- if the scion is PAL‐suppressede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“SAR is not observed if the scion is PAL‐suppressed”
Claim · model-written summary
Treatment of PAL-suppressed tobacco with dichloro-isonicotinic acid induces PR protein expression and SAR against TMV.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- dichloro‐isonicotinic acid (INA)e1
- Outcome
- PR protein expressione1
- Direction
- inducese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“Treatment of PAL‐suppressed plants with dichloro‐isonicotinic acid (INA) induces PR protein expression and SAR against subsequent TMV infection”
Claim · model-written summary
Treatment with SA only partially restores SAR in PAL-suppressed tobacco.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- SAe1
- Outcome
- SARe1
- Qualifier
- only partially restorese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“treatment with SA, while inducing PR proteins, only partially restores SAR”
Claim · model-written summary
De novo synthesis of SA and/or other phenylpropanoids is required for expression of resistance in systemic leaves.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- expression of resistance in systemic leavese1
- Qualifier
- de novo synthesis of SAe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“de novo synthesis of SA, and/or the presence or synthesis of other phenylpropanoids, is required for expression of resistance in systemic leaves”
Claim · model-written summary
The amount of pre-existing phenylpropanoid compounds in systemic leaves may be important for the establishment of SAR.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- establishment of SARe1
- Qualifier
- the amount of pre-existing phenylpropanoid compounds in systemic leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco ( Nicotiana tabacum L. cv. Xanthinc) plants”
e1“the amount of pre-existing phenylpropanoid compounds in systemic leaves, or the ability to synthesize further phenylpropanoids in response to the systemic signal, may be important for the establishment of SAR”
The same questions in other papers
infection · disease · Nicotiana tabacum (tobacco)Positive and negative results
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See all 15 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.