Abstract
Global climate change poses a significant threat to plant growth and crop yield and is exacerbated by environmental factors, such as drought, salinity, greenhouse gasses, and extreme temperatures. Plant growth-promoting rhizobacteria (PGPR) help plants withstand drought. However, the mechanisms underlying PGPR–plant interactions remain unclear. Thus, this study aimed to isolate PGPR, Bacillus megaterium strains CACC109 and CACC119, from a ginseng field and investigate the mechanisms underlying PGPR-stimulated tolerance to drought stress by evaluating their plant growth-promoting activities and effects on rice growth and stress tolerance through in vitro assays, pot experiments, and physiological and molecular analyses. Compared with B. megaterium type strain ATCC14581, CACC109 and CACC119 exhibited higher survival rates under osmotic stress, indicating their potential to enhance drought tolerance. Additionally, CACC109 and CACC119 strains exhibited various plant growth-promoting activities, including phosphate solubilization, nitrogen fixation, indole-3-acetic acid production, siderophore secretion, 1-aminocyclopropane-1-carboxylate deaminase activity, and exopolysaccharide production. After inoculation, CACC109 and CACC119 significantly improved the seed germination of rice ( Oryza sativa L.) under osmotic stress and promoted root growth under stressed and non-stressed conditions. They also facilitated plant growth in pot experiments, as evidenced by increased shoot and root lengths, weights, and leaf widths. Furthermore, CACC109 and CACC119 improved plant physiological characteristics, such as chlorophyll levels, and production of osmolytes, such as proline. In particular, CACC109- and CACC119-treated rice plants showed better drought tolerance, as evidenced by their higher survival rates, greater chlorophyll contents, and lower water loss rates, compared with mock-treated rice plants. Application of CACC109 and CACC119 upregulated the expression of antioxidant-related genes (e.g., OsCAT , OsPOD , OsAPX , and OsSOD ) and drought-responsive genes (e.g., OsWRKY47, OsZIP23, OsDREB2, OsNAC066, OsAREB1, and OsAREB2 ). In conclusion, CACC109 and CACC119 are promising biostimulants for enhancing plant growth and conferring resistance to abiotic stresses in crop production. Future studies should conduct field trials to validate these findings under real agricultural conditions, optimize inoculation methods for practical use, and further investigate the biochemical and physiological responses underlying the observed benefits.
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Claims 15
Claim · model-written summary
CACC109 and CACC119 showed higher survival under osmotic stress than the B. megaterium type strain.
- Taxon
- rice
Oryza sativat0 - Treatment
- osmotic stresse1
- Interactor
- CACC109 and CACC119e1symbiont
- Outcome
- survival ratese1
- Direction
- highere1
- Comparator
- B. megaterium type strain ATCC14581e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“Compared with B. megaterium type strain ATCC14581, CACC109 and CACC119 exhibited higher survival rates under osmotic stress”
Claim · model-written summary
Inoculation with CACC109 and CACC119 significantly improved rice seed germination under osmotic stress.
- Taxon
- riceOryza sativat0
- Treatment
- After inoculatione2
- Interactor
- CACC109 and CACC119e2symbiont
- Outcome
- seed germinatione2
- Direction
- significantly improvede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e2“After inoculation, CACC109 and CACC119 significantly improved the seed germination of rice ( Oryza sativa L.) under osmotic stress”
Claim · model-written summary
Inoculation with CACC109 and CACC119 promoted rice root growth under stressed and non-stressed conditions.
- Taxon
- riceOryza sativat0
- Treatment
- After inoculatione2
- Interactor
- CACC109 and CACC119e2symbiont
- Outcome
- root growthe3
- Direction
- promotede3
- Setting
- stressed and non-stressed conditionse3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e2“After inoculation, CACC109 and CACC119 significantly improved the seed germination of rice ( Oryza sativa L.) under osmotic stress”
e3“promoted root growth under stressed and non-stressed conditions”
Claim · model-written summary
Inoculation with CACC109 and CACC119 increased shoot and root lengths and weights in pot experiments.
- Taxon
- riceOryza sativat0
- Treatment
- After inoculatione2
- Interactor
- CACC109 and CACC119e2symbiont
- Outcome
- shoot and root lengths, weightse4
- Direction
- increasede4
- Setting
- pot experimentse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e2“After inoculation, CACC109 and CACC119 significantly improved the seed germination of rice ( Oryza sativa L.) under osmotic stress”
e4“They also facilitated plant growth in pot experiments, as evidenced by increased shoot and root lengths, weights, and leaf widths”
Claim · model-written summary
Inoculation with CACC109 and CACC119 increased rice leaf width in pot experiments.
- Taxon
- riceOryza sativat0
- Treatment
- After inoculatione2
- Interactor
- CACC109 and CACC119e2symbiont
- Outcome
- leaf widthse4
- Direction
- increasede4
- Setting
- pot experimentse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e2“After inoculation, CACC109 and CACC119 significantly improved the seed germination of rice ( Oryza sativa L.) under osmotic stress”
e4“They also facilitated plant growth in pot experiments, as evidenced by increased shoot and root lengths, weights, and leaf widths”
Claim · model-written summary
CACC109 and CACC119 improved chlorophyll levels in rice.
- Taxon
- riceOryza sativat0
- Treatment
- CACC109 and CACC119e6
- Outcome
- chlorophyll levelse6
- Direction
- improvede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e6“CACC109 and CACC119 improved plant physiological characteristics, such as chlorophyll levels, and production of osmolytes, such as proline”
Claim · model-written summary
CACC109 and CACC119 improved production of osmolytes such as proline in rice.
- Taxon
- riceOryza sativat0
- Treatment
- CACC109 and CACC119e6
- Outcome
- production of osmolytes, such as prolinee6
- Direction
- improvede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e6“CACC109 and CACC119 improved plant physiological characteristics, such as chlorophyll levels, and production of osmolytes, such as proline”
Claim · model-written summary
CACC109- and CACC119-treated rice had higher survival rates under drought than mock-treated plants.
- Taxon
- riceOryza sativat0
- Treatment
- CACC109- and CACC119-treatede1
- Outcome
- survival ratese1
- Direction
- highere1
- Comparator
- mock-treated rice plantse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“CACC109- and CACC119-treated rice plants showed better drought tolerance, as evidenced by their higher survival rates, greater chlorophyll contents, and lower water loss rates, compared with mock-treated rice plants”
Claim · model-written summary
CACC109- and CACC119-treated rice had lower water loss rates under drought than mock-treated plants.
- Taxon
- riceOryza sativat0
- Treatment
- CACC109- and CACC119-treatede1
- Outcome
- water loss ratese1
- Direction
- lowere1
- Comparator
- mock-treated rice plantse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“CACC109- and CACC119-treated rice plants showed better drought tolerance, as evidenced by their higher survival rates, greater chlorophyll contents, and lower water loss rates, compared with mock-treated rice plants”
Claim · model-written summary
Application of CACC109 and CACC119 upregulated antioxidant-related genes OsCAT, OsPOD and OsAPX in rice.
- Taxon
- riceOryza sativat0
- Treatment
- Application of CACC109 and CACC119e1
- Gene
- OsCAT , OsPOD , OsAPXe1
- Outcome
- expression of antioxidant-related genese1
- Direction
- upregulatede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“Application of CACC109 and CACC119 upregulated the expression of antioxidant-related genes (e.g., OsCAT , OsPOD , OsAPX , and OsSOD ) and drought-responsive genes (e.g., OsWRKY47, OsZIP23, OsDREB2, OsNAC066, OsAREB1, and OsAREB2 )”
Claim · model-written summary
Application of CACC109 and CACC119 upregulated antioxidant-related gene OsSOD in rice.
- Taxon
- riceOryza sativat0
- Treatment
- Application of CACC109 and CACC119e1
- Gene
- OsSODe1
- Outcome
- expression of antioxidant-related genese1
- Direction
- upregulatede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“Application of CACC109 and CACC119 upregulated the expression of antioxidant-related genes (e.g., OsCAT , OsPOD , OsAPX , and OsSOD ) and drought-responsive genes (e.g., OsWRKY47, OsZIP23, OsDREB2, OsNAC066, OsAREB1, and OsAREB2 )”
Claim · model-written summary
Application of CACC109 and CACC119 upregulated drought-responsive genes OsWRKY47, OsZIP23 and OsDREB2 in rice.
- Taxon
- riceOryza sativat0
- Treatment
- Application of CACC109 and CACC119e1
- Gene
- OsWRKY47, OsZIP23, OsDREB2e1
- Outcome
- drought-responsive genese1
- Direction
- upregulatede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“Application of CACC109 and CACC119 upregulated the expression of antioxidant-related genes (e.g., OsCAT , OsPOD , OsAPX , and OsSOD ) and drought-responsive genes (e.g., OsWRKY47, OsZIP23, OsDREB2, OsNAC066, OsAREB1, and OsAREB2 )”
Claim · model-written summary
Application of CACC109 and CACC119 upregulated drought-responsive genes OsNAC066, OsAREB1 and OsAREB2 in rice.
- Taxon
- riceOryza sativat0
- Treatment
- Application of CACC109 and CACC119e1
- Gene
- OsNAC066, OsAREB1, and OsAREB2e1
- Outcome
- drought-responsive genese1
- Direction
- upregulatede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“Application of CACC109 and CACC119 upregulated the expression of antioxidant-related genes (e.g., OsCAT , OsPOD , OsAPX , and OsSOD ) and drought-responsive genes (e.g., OsWRKY47, OsZIP23, OsDREB2, OsNAC066, OsAREB1, and OsAREB2 )”
Claim · model-written summary
CACC109 and CACC119 are promising biostimulants for rice growth and abiotic stress resistance in crop production (authors conclude).
- Taxon
- riceOryza sativat0
- Outcome
- promising biostimulants for enhancing plant growthe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“In conclusion, CACC109 and CACC119 are promising biostimulants for enhancing plant growth and conferring resistance to abiotic stresses in crop production”
Claim · model-written summary
CACC109 and CACC119 showed several plant growth-promoting activities in vitro.
- Taxon
- riceOryza sativat0
- Interactor
- CACC109 and CACC119e1symbiont
- Outcome
- plant growth-promoting activitiese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“protect rice (Oryza sativa L.) from drought”
e1“CACC109 and CACC119 strains exhibited various plant growth-promoting activities, including phosphate solubilization, nitrogen fixation, indole-3-acetic acid production, siderophore secretion, 1-aminocyclopropane-1-carboxylate deaminase activity, and exopolysaccharide production”
The same questions in other papers
drought · survival · Oryza sativa (rice)Positive and negative results
3 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
1 paper more in this group
See all 5 papers →inoculation · growth · Oryza sativa (rice)Positive and negative results
361 papers in the same direction as this paper · 34 in the opposite direction · 3 reporting no difference from an alternative
- no effect
- negative
- no effect
395 papers more in this group
See all 399 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.