Abstract
Abstract Tannery wastewater is a major environmental pollutant that introduces toxic compounds, including chromium (Cr), into agricultural soils, posing significant challenges to plant growth and productivity. This research uniquely evaluates the efficacy of three specific plant growth-promoting rhizobacteria (PGPR)— Paenibacillus polymyxa , Bacillus amyloliquefaciens , and Pseudomonas putida —for mitigating Cr stress in rice ( Oryza sativa L.). In this study, O. sativa plants were exposed to different levels of tannery wastewater (0%, 50%, and 100%) in a controlled pot experiment to assess the impact of P. polymyxa , B. amyloliquefaciens and P. putida on various morpho-physio-biochemical traits. Results from the present study revealed that the Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents, calcium (Ca 2+ ), magnesium (Mg 2+ ), iron (Fe 2+ ), and phosphorus (P) contents in the plants. However, Cr stress also induced oxidative stress in the plants by increasing malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ), which also led to an increase in various enzymatic and nonenzymatic antioxidants and also the gene expression and sugar content. Furthermore, a significant ( P < 0.05) increase in proline metabolism, the AsA–GSH cycle, and the pigmentation of cellular components was observed. Addition of P. polymyxa , B. amyloliquefaciens and P. putide into the soil significantly alleviated Cr toxicity effects on O. sativa by improving photosynthetic capacity and ultimately plant growth. Increased activities of antioxidant enzymes in organic acid and PGPRs-treated plants seem to play a role in capturing stress-induced reactive oxygen species as was evident from lower levels of MDA and H 2 O 2 . Moreover, the application of different PGPRs enhanced both the abundance and diversity of the rhizosphere microbiome, with bacterial population levels and Shannon diversity indices significantly increasing. A marked reduction in daily Cr intake and associated health risks was also observed under these treatments, and proteomic responses under Cr stress. Research findings, therefore, suggested that the application of PGPRs can ameliorate Cr toxicity in O. sativa seedlings and resulted in improved plant growth and composition under metal stress.
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Claims 17
Claim · model-written summary
Chromium toxicity reduced rice shoot and root growth and leaf traits.
- Taxon
- rice
Oryza sativat0 - Treatment
- Cr toxicitye0
- Outcome
- shoot length, root length, number of leavese0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium toxicity reduced rice shoot and root biomass.
- Taxon
- riceOryza sativat0
- Treatment
- Cr toxicitye0
- Outcome
- shoot fresh weight, root fresh weight, shoot dry weighte0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium toxicity reduced rice pigments.
- Taxon
- riceOryza sativat0
- Treatment
- Cr toxicitye0
- Outcome
- chlorophyll-a, chlorophyll-b, total chlorophylle0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium toxicity reduced rice gas exchange.
- Taxon
- riceOryza sativat0
- Treatment
- Cr toxicitye0
- Outcome
- net photosynthesis, stomatal conductance, transpiration ratee0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium toxicity reduced rice sugar contents.
- Taxon
- riceOryza sativat0
- Treatment
- Cr toxicitye0
- Outcome
- soluble sugar, reducing sugar, non-reducing sugar contentse0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium toxicity reduced calcium, magnesium and iron contents.
- Taxon
- riceOryza sativat0
- Treatment
- Cr toxicitye0
- Outcome
- calcium (Ca 2+ ), magnesium (Mg 2+ ), iron (Fe 2+ )e0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents, calcium (Ca 2+ ), magnesium (Mg 2+ ), iron (Fe 2+ )”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium toxicity reduced phosphorus content.
- Taxon
- riceOryza sativat0
- Treatment
- Cr toxicitye0
- Outcome
- phosphorus (P) contentse0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr toxicity induced a substantial decrease in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents, calcium (Ca 2+ ), magnesium (Mg 2+ ), iron (Fe 2+ ), and phosphorus (P) contents in the plants”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium stress increased malondialdehyde and hydrogen peroxide.
- Taxon
- riceOryza sativat0
- Treatment
- Cr stresse0
- Outcome
- malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 )e0
- Direction
- increasinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr stress also induced oxidative stress in the plants by increasing malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 )”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium stress increased enzymatic and nonenzymatic antioxidants.
- Taxon
- riceOryza sativat0
- Treatment
- Cr stresse0
- Outcome
- enzymatic and nonenzymatic antioxidantse0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr stress also induced oxidative stress in the plants by increasing malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ), which also led to an increase in various enzymatic and nonenzymatic antioxidants”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Chromium stress increased gene expression and sugar content.
- Taxon
- riceOryza sativat0
- Treatment
- Cr stresse0
- Outcome
- gene expression and sugar contente0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cr stress also induced oxidative stress in the plants by increasing malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ), which also led to an increase in various enzymatic and nonenzymatic antioxidants and also the gene expression and sugar content”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Proline metabolism, the AsA–GSH cycle and cellular pigmentation increased significantly.
- Taxon
- riceOryza sativat0
- Outcome
- proline metabolism, the AsA–GSH cycle, and the pigmentation of cellular componentse0
- Direction
- increasee0
- Value
- P < 0.05e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a significant ( P < 0.05) increase in proline metabolism, the AsA–GSH cycle, and the pigmentation of cellular components was observed”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Paenibacillus polymyxa alleviated chromium toxicity by improving photosynthesis and growth.
- Taxon
- O. sativaOryza sativae0
- Treatment
- P. polymyxae0
- Interactor
- P. polymyxa
Paenibacillus polymyxae0symbiont - Outcome
- photosynthetic capacity and ultimately plant growthe0
- Direction
- improvinge0
- Comparator
- Cr toxicitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of P. polymyxa , B. amyloliquefaciens and P. putide into the soil significantly alleviated Cr toxicity effects on O. sativa by improving photosynthetic capacity and ultimately plant growth”
Claim · model-written summary
Bacillus amyloliquefaciens alleviated chromium toxicity by improving photosynthesis and growth.
- Taxon
- O. sativaOryza sativae0
- Treatment
- B. amyloliquefaciense0
- Interactor
- B. amyloliquefaciens
.jpg?width=60)
Bacillus amyloliquefaciense0symbiont - Outcome
- photosynthetic capacity and ultimately plant growthe0
- Direction
- improvinge0
- Comparator
- Cr toxicitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Addition of P. polymyxa , B. amyloliquefaciens and P. putide into the soil significantly alleviated Cr toxicity effects on O. sativa by improving photosynthetic capacity and ultimately plant growth”
Claim · model-written summary
Pseudomonas putida alleviated chromium toxicity by improving photosynthesis and growth.
- Taxon
- O. sativaOryza sativae0
- Treatment
- P. putidee0
- Interactor
- P. putidee0symbiont
- Outcome
- photosynthetic capacity and ultimately plant growthe0
- Direction
- improvinge0
- Comparator
- Cr toxicitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of P. polymyxa , B. amyloliquefaciens and P. putide into the soil significantly alleviated Cr toxicity effects on O. sativa by improving photosynthetic capacity and ultimately plant growth”
Claim · model-written summary
Antioxidant enzyme activity was higher in treated plants and was linked by the authors to lower MDA and hydrogen peroxide.
- Taxon
- riceOryza sativat0
- Treatment
- PGPRs-treated plantse0
- Outcome
- activities of antioxidant enzymese0
- Direction
- Increasede0
- Qualifier
- lower levels of MDA and H 2 O 2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased activities of antioxidant enzymes in organic acid and PGPRs-treated plants seem to play a role in capturing stress-induced reactive oxygen species as was evident from lower levels of MDA and H 2 O 2”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
PGPR application increased rhizosphere bacterial abundance and diversity.
- Taxon
- riceOryza sativat0
- Treatment
- different PGPRse0
- Interactor
- PGPRse0symbiont
- Outcome
- abundance and diversity of the rhizosphere microbiomee0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“application of different PGPRs enhanced both the abundance and diversity of the rhizosphere microbiome, with bacterial population levels and Shannon diversity indices significantly increasing”
t0“rice (Oryza sativa L.)”
Claim · model-written summary
Daily chromium intake and associated health risks declined under the treatments.
- Taxon
- riceOryza sativat0
- Treatment
- these treatmentse0
- Outcome
- daily Cr intake and associated health riskse0
- Direction
- reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A marked reduction in daily Cr intake and associated health risks was also observed under these treatments”
t0“rice (Oryza sativa L.)”