Abstract
Freezing stress (FS), especially during germination, severely impacts the growth, development, productivity, and distribution of alfalfa ( Medicago sativa L.). Exogenous salicylic acid (SA), a signal molecule involved in abiotic stress responses, effectively improves the FS response of seeds. We investigate changes in seedling phenotype and hormone contents, and perform transcriptome analyses to identify how SA may improve the FS response in alfalfa during germination. Compared with control values, after 16 h FS, exogenous SA promotes seedling lengthening, and increases endogenous contents of jasmonic, abscisic, and gibberellic acids, and decreases indole-3-acetic acid (IAA), and zeatin; after 24 h FS, contents of SA, IAA, and gibberellic and abscisic acids increased, and JA and zeatin content decreased. Phytohormone biosynthesis and signaling pathways genes were induced by SA after FS. Weighted correlation network analysis suggests that GH3.1 and HSP70 play important roles in SA regulation of FS. We report a possible working model, where exogenous SA inhibits GH3.1 expression to decrease IAA content, causing TIR1 to negatively regulate expression of AUX/IAA and auxin response related genes to suppress the IAA signaling pathway, and for TIR1 to repress the SA signaling pathway after FS. For the NPR1-dependent pathway, NPR1 could bind to TGAs to regulate expression of PR1 genes to defend against FS. For the NPR1-independent pathway, superoxide dismutase, ascorbateperoxidase, glutathione-S-transferase, heat shock protein, alternative oxidase, and late embryogenesis abundant encoded genes were induced following FS. • Exogenous SA possible induced NPR1 dependent and NPR1 independent pathway related genes to against freezing stress. • In the NPR1 dependent pathway, NPR1 could bind to TGAs to regulate the expression of PR1 genes to defend against freezing stress. • In the NPR1-independent pathway, mounts genes of SODs, APXs, GSTs, HSPs, AOX s, and LEA s were induced to against freezing stress. • The results of WGCNA analysis suggest that GH3.1 and HSP70 paly the critical role in SA regulate alfalfa against freezing stress. • Exogenous SA could increase endogenous SA content, and inhibit GH3.1 expression to decrease the content of IAA, which affect TIR1 to negative regulate of AUX/IAA and auxin response related genes expression to suppress IAA signaling pathway, and TIR1 repress SA signaling pathway in freezing stress.
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Claims 11
Claim · model-written summary
Salicylic acid promoted seedling lengthening after 16 h freezing stress.
- Taxon
- alfalfa
Medicago sativat0 - Treatment
- exogenous SAe0
- Outcome
- seedling lengtheninge0
- Direction
- promotese0
- Qualifier
- after 16 h FSe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after 16 h FS, exogenous SA promotes seedling lengthening”
t0“alfalfa”
Claim · model-written summary
After 16 h, salicylic acid increased jasmonic, abscisic and gibberellic acids.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- salicylic acidt0
- Outcome
- endogenous contents of jasmonic, abscisic, and gibberellic acidse0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases endogenous contents of jasmonic, abscisic, and gibberellic acids”
t0“salicylic acid promoting alfalfa”
Claim · model-written summary
After 16 h, salicylic acid decreased IAA and zeatin.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- salicylic acidt0
- Outcome
- indole-3-acetic acid (IAA), and zeatine0
- Direction
- decreasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreases indole-3-acetic acid (IAA), and zeatin”
t0“salicylic acid promoting alfalfa”
Claim · model-written summary
After 24 h, SA, IAA and gibberellic acid contents increased.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- salicylic acidt0
- Outcome
- contents of SA, IAA, and gibberellice0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after 24 h FS, contents of SA, IAA, and gibberellic and abscisic acids increased”
t0“salicylic acid promoting alfalfa”
Claim · model-written summary
After 24 h, abscisic acid content increased.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- salicylic acidt0
- Outcome
- abscisic acidse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“gibberellic and abscisic acids increased”
t0“salicylic acid promoting alfalfa”
Claim · model-written summary
After 24 h, JA and zeatin contents decreased.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- salicylic acidt0
- Outcome
- JA and zeatin contente0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“JA and zeatin content decreased”
t0“salicylic acid promoting alfalfa”
Claim · model-written summary
SA induced phytohormone biosynthesis and signaling genes after freezing stress.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- SAe0
- Outcome
- Phytohormone biosynthesis and signaling pathways genese0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phytohormone biosynthesis and signaling pathways genes were induced by SA after FS”
t0“alfalfa”
Claim · model-written summary
Network analysis implicated GH3.1 and HSP70 in SA freezing-stress regulation.
- Taxon
- alfalfaMedicago sativat0
- Gene
- GH3.1 and HSP70e0
- Outcome
- SA regulation of FSe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GH3.1 and HSP70 play important roles in SA regulation of FS”
t0“alfalfa”
Claim · model-written summary
The proposed model has SA suppressing GH3.1 and IAA signaling.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- exogenous SAe0
- Gene
- GH3.1e0
- Outcome
- IAA signaling pathwaye0
- Direction
- suppresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenous SA inhibits GH3.1 expression to decrease IAA content, causing TIR1 to negatively regulate expression of AUX/IAA and auxin response related genes to suppress the IAA signaling pathway”
t0“alfalfa”
Claim · model-written summary
NPR1 may bind TGAs to regulate PR1 expression in freezing defense.
- Taxon
- alfalfaMedicago sativat0
- Gene
- NPR1e0
- Outcome
- defend against FSe0
- Qualifier
- bind to TGAs to regulate expression of PR1 genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NPR1 could bind to TGAs to regulate expression of PR1 genes to defend against FS”
t0“alfalfa”
Claim · model-written summary
NPR1-independent stress response genes were induced after freezing stress.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- encoded genese0
- Direction
- inducede0
- Qualifier
- following FSe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“superoxide dismutase, ascorbateperoxidase, glutathione-S-transferase, heat shock protein, alternative oxidase, and late embryogenesis abundant encoded genes were induced following FS”
t0“alfalfa”
The same questions in other papers
salicylic acid · molecular: metabolites · Medicago sativa (alfalfa)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
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.