Abstract
BACKGROUND: Polyphenol oxidase (PPO), often encoded by a multi-gene family, causes oxidative browning, a significant problem in many food products. Low-browning potatoes were produced previously through suppression of PPO gene expression, but the contribution of individual PPO gene isoform to the oxidative browning process was unknown. Here we investigated the contributions of different PPO genes to total PPO protein activity, and the correlations between PPO protein level, PPO activity and tuber tissue browning potential by suppression of all previously characterized potato PPO genes, both individually and in combination using artificial microRNAs (amiRNAs) technology. RESULTS: Survey of the potato genome database revealed 9 PPO-like gene models, named StuPPO1 to StuPPO9 in this report. StuPPO1, StuPPO2, StuPPO3 and StuPPO4 are allelic to the characterized POTP1/P2, POT32, POT33 and POT72, respectively. Fewer ESTs were found to support the transcriptions of StuPPO5 to StuPPO8. StuPPO9 related ESTs were expressed at significant higher levels in pathogen-infected potato tissues. A series of browning phenotypes were obtained by suppressing StuPPO1 to StuPPO4 genes alone and in combination. Down-regulation of one or several of the PPO genes did not usually cause up-regulation of the other PPO genes in the transgenic potato tubers, but resulted in reduced PPO protein levels. The different PPO genes did not contribute equally to the total PPO protein content in the tuber tissues, with StuPPO2 accounting for ~ 55% as the major contributor, followed by StuPPO1, ~ 25-30% and StuPPO3 and StuPPO4 together with less than 15%. Strongly positive correlations between PPO protein level, PPO activity and browning potential were demonstrated in our analysis. Low PPO activity and low-browning potatoes were produced by simultaneous down-regulation of StuPPO2 to StuPPO4, but the greatest reduction occurred when StuPPO1 to StuPPO4 were all suppressed. CONCLUSION: StuPPO1 to StuPPO4 genes contributed to browning reactions in tuber tissues but their effect was not equal. Different PPO genes may be regulated independently reflecting their diversified functions. Our results show that amiRNAs can be used to suppress closely related members of highly conserved multi-gene family. This approach also suggests a new strategy for breeding low-browning crops using small DNA inserts.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 15
Claim · model-written summary
The potato genome survey found nine PPO-like gene models.
- Taxon
- potato
Solanum tuberosume0 - Gene
- StuPPO1 to StuPPO9e0
- Outcome
- PPO-like gene modelse0
- Value
- 9e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Survey of the potato genome database revealed 9 PPO-like gene models, named StuPPO1 to StuPPO9 in this report.”
Claim · model-written summary
StuPPO1 through StuPPO4 were allelic to previously characterized POT genes.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- StuPPO1, StuPPO2, StuPPO3 and StuPPO4e0
- Outcome
- allelic to the characterized POTP1/P2, POT32, POT33 and POT72e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“StuPPO1, StuPPO2, StuPPO3 and StuPPO4 are allelic to the characterized POTP1/P2, POT32, POT33 and POT72, respectively.”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
Fewer ESTs supported transcription of StuPPO5 through StuPPO8.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- StuPPO5 to StuPPO8e0
- Outcome
- ESTse0
- Direction
- Fewere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fewer ESTs were found to support the transcriptions of StuPPO5 to StuPPO8.”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
StuPPO9-related EST expression was significantly higher in pathogen-infected potato tissues.
- Taxon
- potatoSolanum tuberosume0
- Gene
- StuPPO9e0
- Outcome
- ESTs were expressede0
- Direction
- highere0
- Qualifier
- pathogen-infected potato tissuese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“StuPPO9 related ESTs were expressed at significant higher levels in pathogen-infected potato tissues.”
Claim · model-written summary
Suppression of StuPPO1 through StuPPO4 alone or together yielded multiple browning phenotypes.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- suppressing StuPPO1 to StuPPO4 genes alone and in combinatione0
- Gene
- StuPPO1 to StuPPO4e0
- Outcome
- series of browning phenotypese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A series of browning phenotypes were obtained by suppressing StuPPO1 to StuPPO4 genes alone and in combination.”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
Down-regulating PPO genes usually did not up-regulate other PPO genes.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Down-regulation of one or several of the PPO genese0
- Outcome
- up-regulation of the other PPO genese0
- Direction
- did not usually causee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Down-regulation of one or several of the PPO genes did not usually cause up-regulation of the other PPO genes in the transgenic potato tubers”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
Down-regulating PPO genes reduced PPO protein levels.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Down-regulation of one or several of the PPO genese0
- Outcome
- PPO protein levelse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Down-regulation of one or several of the PPO genes did not usually cause up-regulation of the other PPO genes in the transgenic potato tubers, but resulted in reduced PPO protein levels.”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
StuPPO2 contributed about 55% of total tuber PPO protein.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- StuPPO2e0
- Outcome
- major contributore0
- Value
- ~ 55%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“StuPPO2 accounting for ~ 55% as the major contributor”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
StuPPO1 contributed about 25 to 30% of total tuber PPO protein.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- StuPPO1e0
- Outcome
- StuPPO1e0
- Value
- ~ 25-30%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“StuPPO1, ~ 25-30%”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
StuPPO3 and StuPPO4 together contributed less than 15% of total tuber PPO protein.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- StuPPO3 and StuPPO4e0
- Outcome
- StuPPO3 and StuPPO4 togethere0
- Value
- less than 15%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“StuPPO3 and StuPPO4 together with less than 15%”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
PPO protein level, PPO activity, and browning potential were strongly positively correlated.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- PPOe0
- Outcome
- browning potentiale0
- Direction
- positivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strongly positive correlations between PPO protein level, PPO activity and browning potential were demonstrated in our analysis.”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
Simultaneous StuPPO2 through StuPPO4 down-regulation produced low PPO activity and low-browning potatoes.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- simultaneous down-regulation of StuPPO2 to StuPPO4e0
- Gene
- StuPPO2 to StuPPO4e0
- Outcome
- PPO activity and low-browning potatoese0
- Direction
- Lowe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low PPO activity and low-browning potatoes were produced by simultaneous down-regulation of StuPPO2 to StuPPO4”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
Suppression of StuPPO1 through StuPPO4 gave the greatest reduction in browning.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- StuPPO1 to StuPPO4 were all suppressede0
- Gene
- StuPPO1 to StuPPO4e0
- Outcome
- reductione0
- Direction
- greatest reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the greatest reduction occurred when StuPPO1 to StuPPO4 were all suppressed”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
amiRNAs can suppress closely related members of a conserved gene family.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- suppress closely related members of highly conserved multi-gene familye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“amiRNAs can be used to suppress closely related members of highly conserved multi-gene family”
t0“potato (Solanum tuberosum L.)”
Claim · model-written summary
The authors suggest using small DNA inserts to breed low-browning crops.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- breeding low-browning crops using small DNA insertse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This approach also suggests a new strategy for breeding low-browning crops using small DNA inserts.”
t0“potato (Solanum tuberosum L.)”
The same questions in other papers
polyphenol · physiology: antioxidant enzymes · Solanum tuberosum (potato)Results agree
2 papers in the same direction as this paper
- positive
- positive
loss of function · physiology: antioxidant enzymes · Solanum tuberosum (potato)Results agree
2 papers in the same direction as this paper
- positive
- positive
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.