Abstract
Soil salinization is increasingly recognized as a critical environmental challenge that significantly threatens plant survival and agricultural productivity. To elucidate the mechanism of salt resistance in poplar, physiological and transcriptomic analyses were conducted on 84K poplar (Populus alba × Populus glandulosa) under varying salt concentrations (0, 100, 200 and 300 mM NaCl). As salt levels increased, observable damage to poplar progressively intensified. Differentially expressed genes under salt stress were primarily enriched in photosynthesis, redox activity and glutathione metabolism pathways. Salt stress reduced chlorophyll content and net photosynthetic rate, accompanied by the downregulation of photosynthesis-related genes. NaCl (300 mM) significantly inhibited the photochemical activity of photosystems. The higher photochemical activity under 100 and 200 mM NaCl was attributed to the activated PGR5-cyclic electron flow photoprotective mechanism. However, the NAD(P)H dehydrogenase-like (NDH)-cyclic electron flow was inhibited under all salt levels. Salt stress led to reactive oxygen species accumulation, activating the ASA-GSH cycle and antioxidant enzymes to mitigate oxidative damage. Weighted gene co-expression network analysis showed that five photosynthesis-related hub genes (e.g., FNR and TPI) were down-regulated and nine antioxidant-related hub genes (e.g., GRX, GPX and GST) were up-regulated under salt stress conditions. PagGRXC9 encodes glutaredoxin and was found to be differentially expressed during the salt stress condition. Functional studies showed that overexpressing PagGRXC9 enhanced salt tolerance in yeast, and in poplar, it improved growth, FV/FM, non-photochemical quenching values and resistance to H2O2-induced oxidative stress under salt stress. This study constructed the photosynthetic and antioxidant response network for salt stress in poplar, revealing that PagGRXC9 enhances salt tolerance by reducing photoinhibition and increasing antioxidant capacity. These findings provide valuable insights for breeding salt-tolerant forest trees.
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Claims 13
Claim · model-written summary
Poplar damage intensified as salt increased.
PopulusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As salt levels increased, observable damage to poplar progressively intensified.”
Claim · model-written summary
Salt stress enriched differential genes in photosynthesis, redox and glutathione pathways.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Differentially expressed genes under salt stress were primarily enriched in photosynthesis, redox activity and glutathione metabolism pathways.”
t0“poplar”
Claim · model-written summary
Salt stress reduced chlorophyll content and net photosynthetic rate.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salt stress reduced chlorophyll content and net photosynthetic rate”
t0“poplar”
Claim · model-written summary
Salt stress downregulated photosynthesis-related genes.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“accompanied by the downregulation of photosynthesis-related genes.”
t0“poplar”
t1“salt stress”
Claim · model-written summary
300 mM NaCl significantly inhibited photosystem photochemical activity.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NaCl (300 mM) significantly inhibited the photochemical activity of photosystems.”
t0“poplar”
Claim · model-written summary
PGR5 cyclic electron flow was activated under 100 and 200 mM NaCl.
- Treatment
- 100 and 200 mM NaCle0
- Outcome
- PGR5-cyclic electron flow photoprotective mechanisme0
- Direction
- activatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The higher photochemical activity under 100 and 200 mM NaCl was attributed to the activated PGR5-cyclic electron flow photoprotective mechanism.”
t0“poplar”
Claim · model-written summary
NDH cyclic electron flow was inhibited under all salt levels.
- Treatment
- all salt levelse0
- Outcome
- NAD(P)H dehydrogenase-like (NDH)-cyclic electron flowe0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the NAD(P)H dehydrogenase-like (NDH)-cyclic electron flow was inhibited under all salt levels.”
t0“poplar”
Claim · model-written summary
Salt stress caused reactive oxygen species accumulation.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salt stress led to reactive oxygen species accumulation”
t0“poplar”
Claim · model-written summary
Salt stress activated the ASA-GSH cycle and antioxidant enzymes.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activating the ASA-GSH cycle and antioxidant enzymes to mitigate oxidative damage.”
t0“poplar”
t1“salt stress”
Claim · model-written summary
Five photosynthesis hub genes were downregulated under salt stress.
- Treatment
- salt stress conditionse0
- Outcome
- photosynthesis-related hub genese0
- Direction
- down-regulatede0
- Value
- fivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“five photosynthesis-related hub genes (e.g., FNR and TPI) were down-regulated and nine antioxidant-related hub genes (e.g., GRX, GPX and GST) were up-regulated under salt stress conditions.”
t0“poplar”
Claim · model-written summary
Nine antioxidant hub genes were upregulated under salt stress.
- Treatment
- salt stress conditionse0
- Outcome
- antioxidant-related hub genese0
- Direction
- up-regulatede0
- Value
- ninee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“five photosynthesis-related hub genes (e.g., FNR and TPI) were down-regulated and nine antioxidant-related hub genes (e.g., GRX, GPX and GST) were up-regulated under salt stress conditions.”
t0“poplar”
Claim · model-written summary
PagGRXC9 was differentially expressed under salt stress.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PagGRXC9 encodes glutaredoxin and was found to be differentially expressed during the salt stress condition.”
t0“poplar”
Claim · model-written summary
PagGRXC9 overexpression improved poplar growth, FV/FM, non-photochemical quenching and oxidative stress resistance under salt stress.
- Treatment
- overexpressing PagGRXC9e1
- Outcome
- growth, FV/FM, non-photochemical quenching valuese0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in poplar, it improved growth, FV/FM, non-photochemical quenching values and resistance to H2O2-induced oxidative stress under salt stress.”
e1“overexpressing PagGRXC9”
The same questions in other papers
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salinity · physiology: oxidative · Populus (poplar)Positive and negative results
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2 papers in the same direction as this paper · 2 in the opposite direction
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1 paper in the same direction as this paper
- negative
salinity · molecular: metabolites · Populus (poplar)Results agree
2 papers in the same direction as this paper
- negative
- negative
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.