Abstract
L.), yet the metabolic determinants underlying cultivar-specific cold tolerance remain insufficiently understood. In this study, we compared a cold-tolerant cultivar ('WL343') and a cold-sensitive cultivar ('Gannong No. 4') using an integrated framework combining physiological analyses, non-targeted metabolomics, and functional validation with exogenous melatonin. Cold stress caused pronounced membrane damage, oxidative stress, and growth inhibition in 'Gannong No. 4', whereas 'WL343' maintained greater membrane integrity, stronger antioxidant capacity, and enhanced osmotic adjustment. Metabolomic profiling revealed extensive cold-induced metabolic reprogramming in both cultivars, but with distinct pathway prioritization. Notably, the tryptophan-melatonin metabolic pathway was specifically and strongly activated in 'WL343', leading to significant endogenous melatonin accumulation, while 'Gannong No. 4' exhibited a weaker response and preferential regulation of secondary metabolism, particularly isoflavonoid-related pathways. Functional experiments further demonstrated that exogenous melatonin markedly alleviated cold-induced injury in 'Gannong No. 4' by reducing reactive oxygen species accumulation, stabilizing membranes, and enhancing antioxidant enzyme activities and osmolyte accumulation. Among the tested concentrations, 100 μM melatonin conferred the greatest protective effect. Collectively, these results identify melatonin as a key functional metabolite underlying cold tolerance in alfalfa and highlight the tryptophan-melatonin pathway as a central metabolic hub conferring cultivar-specific cold resilience. This study provides a metabolic basis for improving alfalfa cold tolerance through breeding and targeted cultivation strategies.
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Claims 12
Claim · model-written summary
Cold stress caused membrane damage, oxidative stress and growth inhibition in Gannong No. 4.
- Taxon
- Alfalfa
Medicago sativat0 - Material
- 'Gannong No. 4'e0
- Treatment
- Cold stresse0
- Outcome
- membrane damage, oxidative stress, and growth inhibitione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cold stress caused pronounced membrane damage, oxidative stress, and growth inhibition in 'Gannong No. 4'”
t0“Alfalfa”
Claim · model-written summary
WL343 maintained greater membrane integrity, antioxidant capacity and osmotic adjustment under cold stress.
- Taxon
- AlfalfaMedicago sativat0
- Material
- 'WL343'e0
- Outcome
- membrane integrity, stronger antioxidant capacity, and enhanced osmotic adjustmente0
- Direction
- greatere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“'WL343' maintained greater membrane integrity, stronger antioxidant capacity, and enhanced osmotic adjustment”
t0“Alfalfa”
Claim · model-written summary
Cold caused extensive metabolic reprogramming in both cultivars, with different pathway priorities.
- Taxon
- AlfalfaMedicago sativat0
- Outcome
- cold-induced metabolic reprogramminge0
- Qualifier
- distinct pathway prioritizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Metabolomic profiling revealed extensive cold-induced metabolic reprogramming in both cultivars, but with distinct pathway prioritization.”
t0“Alfalfa”
Claim · model-written summary
The tryptophan-melatonin pathway was strongly activated in WL343.
- Taxon
- AlfalfaMedicago sativat0
- Material
- 'WL343'e0
- Outcome
- tryptophan-melatonin metabolic pathwaye0
- Direction
- strongly activatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the tryptophan-melatonin metabolic pathway was specifically and strongly activated in 'WL343'”
t0“Alfalfa”
Claim · model-written summary
WL343 accumulated significantly more endogenous melatonin.
- Taxon
- AlfalfaMedicago sativat0
- Outcome
- endogenous melatonin accumulatione0
- Direction
- accumulatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant endogenous melatonin accumulation”
t0“Alfalfa”
Claim · model-written summary
Gannong No. 4 showed a weaker metabolic response.
- Taxon
- AlfalfaMedicago sativat0
- Material
- 'Gannong No. 4'e0
- Outcome
- responsee0
- Direction
- weakere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“'Gannong No. 4' exhibited a weaker response”
t0“Alfalfa”
Claim · model-written summary
Gannong No. 4 preferentially regulated secondary metabolism, particularly isoflavonoid pathways.
- Taxon
- AlfalfaMedicago sativat0
- Outcome
- secondary metabolism, particularly isoflavonoid-related pathwayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“preferential regulation of secondary metabolism, particularly isoflavonoid-related pathways.”
t0“Alfalfa”
Claim · model-written summary
Exogenous melatonin alleviated cold injury in Gannong No. 4.
- Taxon
- AlfalfaMedicago sativat0
- Material
- 'Gannong No. 4'e0
- Treatment
- exogenous melatonine0
- Outcome
- cold-induced injurye0
- Direction
- alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenous melatonin markedly alleviated cold-induced injury in 'Gannong No. 4'”
t0“Alfalfa”
Claim · model-written summary
Exogenous melatonin reduced reactive oxygen species accumulation.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- exogenous melatonine1
- Outcome
- reactive oxygen species accumulatione0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“by reducing reactive oxygen species accumulation”
t0“Alfalfa”
e1“exogenous melatonin markedly alleviated cold-induced injury in 'Gannong No. 4'”
Claim · model-written summary
Exogenous melatonin stabilized membranes.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- exogenous melatonine1
- Outcome
- membranese0
- Direction
- stabilizinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“stabilizing membranes”
t0“Alfalfa”
e1“exogenous melatonin markedly alleviated cold-induced injury in 'Gannong No. 4'”
Claim · model-written summary
Exogenous melatonin enhanced antioxidant enzyme activity and osmolyte accumulation.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- exogenous melatonine1
- Outcome
- antioxidant enzyme activities and osmolyte accumulatione0
- Direction
- enhancinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“enhancing antioxidant enzyme activities and osmolyte accumulation.”
t0“Alfalfa”
e1“exogenous melatonin markedly alleviated cold-induced injury in 'Gannong No. 4'”
Claim · model-written summary
The 100 μM melatonin treatment conferred the greatest protection.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- 100 μM melatonine0
- Outcome
- protective effecte0
- Direction
- greateste0
- Comparator
- tested concentrationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among the tested concentrations, 100 μM melatonin conferred the greatest protective effect.”
t0“Alfalfa”
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See all 14 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.