Abstract
Saline–alkali stress is a severe abiotic factor that limits plant growth and development. Endophytic bacteria can improve plant tolerance to such stress through various mechanism, including osmoregulatory substance accumulation and antioxidant enzyme activity. In this study, four saline–alkali-tolerant endophytic strains, designated SYM-2, SYM-4, SYM-9, and SYM-15, were isolated from the roots of alfalfa grown in saline–alkali soil. Though 16S rDNA sequencing, morphological observations, and physiological–biochemical characterization, the strains were identified as closely related to Bacillus cereus, B. thuringiensis, B. halotolerans, and Pantoea agglomerans, respectively. These strains demonstrated the ability to produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase, siderophores, and indole-3-acetic acid (IAA), as well as solubilizing phosphorus. Under saline–alkali conditions, inoculation with these strains significantly increased alfalfa growth parameters. Plant height increased by 4.07–33.90% and root length by 7.49–27.94%, and fresh and dry weight (both above and below ground) increased compared with the control. Strain SYM-15 showed the highest promoting effects, increasing plant height by 33.90%, root length by 27.94% and shoot dry weight by 59.26%. Additionally, root activity increased by 11.23–40%, proline content by 19.09–129–87%, and soluble protein by 7.71–42.49%, and the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) were significantly elevated across treatments. At the same time, inoculation reduced the levels of hydrogen peroxide (H2O2), superoxide anion (O2−), and malondialdehyde (MDA). Compared with the control and other treatments, including SYM-9, the peroxidase activity and superoxide dismutase activity of alfalfa significantly increased after the SYM-15 treatment, while hydrogen peroxide content, phosphorus content, and neutral detergent fiber and acid detergent fiber contents decreased (p < 0.05). Therefore, SYM-15 plays an important role in promoting growth and represents a promising, high-quality strain resource for the large-scale development of microbials aimed at improving alfalfa tolerance under saline–alkali conditions.
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
Four endophytic strains were identified as related to four named bacterial species, respectively.
- Taxon
- alfalfa
Medicago sativat0 - Interactor
- Bacillus cereus
Bacillus cereuse0symbionte1 - Outcome
- identified as closely related to Bacillus cereus, B. thuringiensis, B. halotolerans, and Pantoea agglomeranse0
- Qualifier
- SYM-2, SYM-4, SYM-9, and SYM-15e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the strains were identified as closely related to Bacillus cereus, B. thuringiensis, B. halotolerans, and Pantoea agglomerans, respectively”
t0“Alfalfa”
e1“four saline–alkali-tolerant endophytic strains, designated SYM-2, SYM-4, SYM-9, and SYM-15, were isolated from the roots of alfalfa”
Claim · model-written summary
The four strains produced ACC deaminase, siderophores, and IAA and solubilized phosphorus.
- Taxon
- alfalfaMedicago sativat0
- Interactor
- endophytic strainse1symbiont
- Outcome
- produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase, siderophores, and indole-3-acetic acid (IAA)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These strains demonstrated the ability to produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase, siderophores, and indole-3-acetic acid (IAA), as well as solubilizing phosphorus”
t0“Alfalfa”
e1“endophytic strains, designated SYM-2, SYM-4, SYM-9, and SYM-15”
Claim · model-written summary
Strain inoculation increased alfalfa height by 4.07–33.90% under saline–alkali conditions.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculation with these strainse1
- Interactor
- strainse1symbiont
- Outcome
- Plant heighte0
- Direction
- increasede0
- Value
- 4.07–33.90%e0
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant height increased by 4.07–33.90% and root length by 7.49–27.94%”
t0“Alfalfa”
e1“inoculation with these strains significantly increased alfalfa growth parameters”
e2“compared with the control”
Claim · model-written summary
Strain inoculation increased alfalfa root length by 7.49–27.94%.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculation with these strainse1
- Interactor
- strainse1symbiont
- Outcome
- root lengthe0
- Direction
- increasede1
- Value
- 7.49–27.94%e0
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“root length by 7.49–27.94%”
t0“Alfalfa”
e1“inoculation with these strains significantly increased alfalfa growth parameters. Plant height increased”
e2“compared with the control”
Claim · model-written summary
Inoculation increased aboveground and belowground fresh and dry weight relative to control.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculation with these strainse1
- Interactor
- strainse1symbiont
- Outcome
- fresh and dry weight (both above and below ground)e0
- Direction
- increasede0
- Comparator
- controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fresh and dry weight (both above and below ground) increased compared with the control”
t0“Alfalfa”
e1“inoculation with these strains significantly increased alfalfa growth parameters”
Claim · model-written summary
SYM-15 increased alfalfa height by 33.90%.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- Strain SYM-15e0
- Interactor
- SYM-15e0symbiont
- Outcome
- plant heighte0
- Direction
- increasinge0
- Value
- 33.90%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strain SYM-15 showed the highest promoting effects, increasing plant height by 33.90%”
t0“Alfalfa”
Claim · model-written summary
SYM-15 increased alfalfa root length by 27.94%.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- SYM-15e1
- Interactor
- SYM-15e1symbiont
- Outcome
- root lengthe0
- Direction
- increasinge1
- Value
- 27.94%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“root length by 27.94%”
t0“Alfalfa”
e1“Strain SYM-15 showed the highest promoting effects, increasing plant height”
Claim · model-written summary
SYM-15 increased shoot dry weight by 59.26%.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- SYM-15e1
- Interactor
- SYM-15e1symbiont
- Outcome
- shoot dry weighte0
- Direction
- increasinge1
- Value
- 59.26%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shoot dry weight by 59.26%”
t0“Alfalfa”
e1“Strain SYM-15 showed the highest promoting effects, increasing plant height”
Claim · model-written summary
Inoculation increased alfalfa root activity by 11.23–40%.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculatione1
- Interactor
- strainse1symbiont
- Outcome
- root activitye0
- Direction
- increasede0
- Value
- 11.23–40%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“root activity increased by 11.23–40%”
t0“Alfalfa”
e1“inoculation with these strains”
Claim · model-written summary
Inoculation increased proline content by the reported 19.09–129–87%, whose range appears malformed.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculatione1
- Interactor
- strainse1symbiont
- Outcome
- proline contente0
- Direction
- increasede2
- Value
- 19.09–129–87%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“proline content by 19.09–129–87%”
t0“Alfalfa”
e1“inoculation with these strains”
e2“root activity increased”
Claim · model-written summary
Inoculation increased soluble protein by 7.71–42.49%.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculatione1
- Interactor
- strainse1symbiont
- Outcome
- soluble proteine0
- Direction
- increasede2
- Value
- 7.71–42.49%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soluble protein by 7.71–42.49%”
t0“Alfalfa”
e1“inoculation with these strains”
e2“root activity increased”
Claim · model-written summary
Inoculation significantly elevated CAT, POD, and SOD activity.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculatione1
- Interactor
- strainse1symbiont
- Outcome
- activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD)e0
- Direction
- elevatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) were significantly elevated across treatments”
t0“Alfalfa”
e1“inoculation with these strains”
Claim · model-written summary
Inoculation reduced H2O2, superoxide anion, and MDA levels.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- inoculatione0
- Interactor
- strainse1symbiont
- Outcome
- levels of hydrogen peroxide (H2O2), superoxide anion (O2−), and malondialdehyde (MDA)e0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inoculation reduced the levels of hydrogen peroxide (H2O2), superoxide anion (O2−), and malondialdehyde (MDA)”
t0“Alfalfa”
e1“inoculation with these strains”
Claim · model-written summary
SYM-15 increased peroxidase and superoxide dismutase activity compared with control and other treatments.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- SYM-15 treatmente0
- Interactor
- SYM-15e0symbiont
- Outcome
- peroxidase activity and superoxide dismutase activitye0
- Direction
- increasede0
- Comparator
- control and other treatments, including SYM-9e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with the control and other treatments, including SYM-9, the peroxidase activity and superoxide dismutase activity of alfalfa significantly increased after the SYM-15 treatment”
Claim · model-written summary
SYM-15 decreased hydrogen peroxide, phosphorus, and detergent fiber contents compared with control and other treatments.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- SYM-15 treatmente1
- Interactor
- SYM-15e1symbiont
- Outcome
- hydrogen peroxide content, phosphorus content, and neutral detergent fiber and acid detergent fiber contentse0
- Direction
- decreasede0
- Comparator
- control and other treatments, including SYM-9e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hydrogen peroxide content, phosphorus content, and neutral detergent fiber and acid detergent fiber contents decreased (p < 0.05)”
t0“Alfalfa”
e1“Compared with the control and other treatments, including SYM-9, the peroxidase activity and superoxide dismutase activity of alfalfa significantly increased after the SYM-15 treatment”
The same questions in other papers
inoculation · physiology: osmolytes · Medicago sativa (alfalfa)Positive and negative results
11 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- positive
9 papers more in this group
See all 13 papers →inoculation · growth · Medicago sativa (alfalfa)Positive and negative results
120 papers in the same direction as this paper · 15 in the opposite direction · 1 reporting no difference from an alternative
- positive
- no effect
- no effect
133 papers more in this group
See all 137 papers →inoculation · physiology: oxidative · Medicago sativa (alfalfa)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
inoculation · physiology: antioxidant enzymes · Medicago sativa (alfalfa)Results agree
10 papers in the same direction as this paper
- positive
- positive
- positive
7 papers more in this group
See all 11 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.