Abstract
Salt stress poses a significant threat to crop yields worldwide. Melatonin (MT), an endogenous hormone synthesized in plants, has emerged as a crucial player in plant responses to various abiotic stresses, including drought, salinity, heat, and cold. However, the precise molecular mechanisms underlying MT-mediated abiotic stress responses remain incompletely understood. To elucidate the key genes and pathways involved in MT-mediated alleviation of salt stress, we conducted physiological, biochemical, and transcriptomic analyses on alfalfa seedlings. Our results demonstrated that alfalfa seedlings treated with melatonin exhibited higher germination rates, longer bud lengths, and greater fresh weights compared to those subjected to salt stress alone. Furthermore, the levels of malondialdehyde (MDA) and superoxide anion (O2−) were reduced, while the activities and contents of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and glutathione (GSH) increased in response to melatonin treatment. Transcriptome analysis revealed 2181 differentially expressed genes (DEGs) in the salt-treated group, with 780 upregulated and 1401 downregulated genes. In contrast, the MT-treated group exhibited 4422 DEGs, including 1438 upregulated and 2984 downregulated genes. Functional annotation and pathway enrichment analysis indicated that DEGs were primarily involved in the biosynthesis of flavonoids, isoflavones, plant hormones, glutathione (GSH), soluble sugars, and other substances, as well as in ABC transporter and MAPK signaling pathways. Notably, the MT-treated group showed greater enrichment of DEGs in these pathways, suggesting that MT mitigates salt stress by modulating the expression of genes related to phytohormones and antioxidant capacity. Overall, our findings provide valuable insights into the molecular mechanisms underlying MT-mediated salt tolerance in alfalfa, with important implications for breeding salt-tolerant alfalfa and other crops.
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Claims 8
Claim · model-written summary
Alfalfa seedlings treated with melatonin showed higher germination rates, longer bud lengths and greater fresh weights than seedlings under salt stress alone.
- Taxon
- alfalfa
Medicago sativae0 - Treatment
- melatonine0
- Outcome
- germination rates, longer bud lengths, and greater fresh weightse0
- Direction
- highere0
- Comparator
- salt stress alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“alfalfa seedlings treated with melatonin exhibited higher germination rates, longer bud lengths, and greater fresh weights compared to those subjected to salt stress alone”
Claim · model-written summary
Levels of malondialdehyde and superoxide anion were reduced by melatonin treatment.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- melatonin treatmente1
- Outcome
- levels of malondialdehyde (MDA) and superoxide anion (O2−)e0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the levels of malondialdehyde (MDA) and superoxide anion (O2−) were reduced”
e1“melatonin treatment”
t0“Alfalfa”
Claim · model-written summary
Activities and contents of antioxidant enzymes such as SOD, POD and GSH increased with melatonin treatment.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- melatonin treatmente0
- Outcome
- activities and contents of antioxidant enzymese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activities and contents of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and glutathione (GSH) increased in response to melatonin treatment”
t0“Alfalfa”
Claim · model-written summary
The salt-treated group had 2181 differentially expressed genes, 780 upregulated and 1401 downregulated.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- salt-treated groupe0
- Outcome
- differentially expressed genes (DEGs)e0
- Value
- 2181e0
- Qualifier
- 780 upregulated and 1401 downregulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transcriptome analysis revealed 2181 differentially expressed genes (DEGs) in the salt-treated group, with 780 upregulated and 1401 downregulated genes”
t0“Alfalfa”
Claim · model-written summary
The melatonin-treated group had 4422 DEGs, 1438 upregulated and 2984 downregulated.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- MT-treated groupe0
- Outcome
- DEGse0
- Value
- 4422e0
- Qualifier
- 1438 upregulated and 2984 downregulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the MT-treated group exhibited 4422 DEGs, including 1438 upregulated and 2984 downregulated genes”
t0“Alfalfa”
Claim · model-written summary
DEGs were primarily involved in biosynthesis of flavonoids, isoflavones, plant hormones, GSH and soluble sugars, and in ABC transporter and MAPK signaling pathways.
- Taxon
- AlfalfaMedicago sativat0
- Outcome
- biosynthesis of flavonoids, isoflavones, plant hormones, glutathione (GSH), soluble sugarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“DEGs were primarily involved in the biosynthesis of flavonoids, isoflavones, plant hormones, glutathione (GSH), soluble sugars, and other substances, as well as in ABC transporter and MAPK signaling pathways”
t0“Alfalfa”
Claim · model-written summary
The melatonin-treated group showed greater enrichment of DEGs in these pathways.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- MT-treated groupe0
- Outcome
- enrichment of DEGse0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the MT-treated group showed greater enrichment of DEGs in these pathways”
t0“Alfalfa”
Claim · model-written summary
The authors suggest melatonin mitigates salt stress by modulating expression of genes related to phytohormones and antioxidant capacity.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- MTe0
- Gene
- genes related to phytohormones and antioxidant capacitye0
- Outcome
- mitigates salt stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MT mitigates salt stress by modulating the expression of genes related to phytohormones and antioxidant capacity”
t0“Alfalfa”
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