Abstract
Melatonin (MT), as a signaling molecule, plays a vital role in regulating leaf senescence in plants. This study aimed to verify the antioxidant roles of MT in delaying dark- or age-induced leaf senescence of cucumber plants. The results showed that endogenous MT responds to darkness and overexpression of CsASMT, the key gene of MT synthesis, and delays leaf senescence stimulated by darkness, as manifested by significantly lower malonaldehyde (MDA) and reactive oxygen species (ROS) contents as well as higher activities and gene expression of antioxidant enzymes compared to the control. Moreover, MT suppressed both age- or dark-induced leaf senescence of cucumber, as evidenced by a decrease in senescence-related gene SAG20 and cell-death-related gene PDCD expression and ROS content and an increase in antioxidant capacity and chlorophyll biosynthesis compared with the H2O-treated seedlings. Meanwhile, the suppression of age-induced leaf senescence by melatonin was also reflected by the reduction in abscisic acid (ABA) biosynthesis and signaling pathways as well as the promotion of auxin (IAA) biosynthesis and signaling pathways in cucumber plants in the solar greenhouse. Combining the results of the two separate experiments, we demonstrated that MT acts as a powerful antioxidant to alleviate leaf senescence by activating the antioxidant system and IAA synthesis and signaling while inhibiting ABA synthesis and signaling in cucumber plants.
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Claims 9
Claim · model-written summary
Endogenous melatonin responded to darkness.
- Taxon
- Cucumber
Cucumis sativust0 - Outcome
- endogenous MTe0
- Qualifier
- darknesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“endogenous MT responds to darkness”
t0“Cucumber”
Claim · model-written summary
CsASMT overexpression delayed dark-induced leaf senescence.
- Taxon
- CucumberCucumis sativust0
- Treatment
- overexpression of CsASMTe0
- Gene
- CsASMTe0
- Outcome
- leaf senescence stimulated by darknesse0
- Direction
- delayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“overexpression of CsASMT, the key gene of MT synthesis, and delays leaf senescence stimulated by darkness”
t0“Cucumber”
Claim · model-written summary
CsASMT overexpression lowered MDA and ROS contents versus the control.
- Taxon
- CucumberCucumis sativust1
- Treatment
- overexpression of CsASMTt0
- Outcome
- malonaldehyde (MDA) and reactive oxygen species (ROS) contentse0
- Direction
- lowere0
- Comparator
- controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly lower malonaldehyde (MDA) and reactive oxygen species (ROS) contents as well as higher activities and gene expression of antioxidant enzymes compared to the control”
t0“overexpression of CsASMT, the key gene of MT synthesis”
t1“Cucumber”
Claim · model-written summary
CsASMT overexpression raised antioxidant enzyme activity and gene expression versus control.
- Taxon
- CucumberCucumis sativust1
- Treatment
- overexpression of CsASMTt0
- Outcome
- activities and gene expression of antioxidant enzymese0
- Direction
- highere0
- Comparator
- controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher activities and gene expression of antioxidant enzymes compared to the control”
t0“overexpression of CsASMT, the key gene of MT synthesis”
t1“Cucumber”
Claim · model-written summary
Melatonin suppressed age- and dark-induced cucumber leaf senescence.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- MTe0
- Outcome
- age- or dark-induced leaf senescencee0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MT suppressed both age- or dark-induced leaf senescence of cucumber”
Claim · model-written summary
Melatonin reduced SAG20 and PDCD expression and ROS relative to water treatment.
- Taxon
- CucumberCucumis sativust0
- Treatment
- Melatonint0
- Outcome
- SAG20 and cell-death-related gene PDCD expression and ROS contente0
- Direction
- decreasee0
- Comparator
- H2O-treated seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a decrease in senescence-related gene SAG20 and cell-death-related gene PDCD expression and ROS content and an increase in antioxidant capacity and chlorophyll biosynthesis compared with the H2O-treated seedlings”
t0“Melatonin Positively Regulates Both Dark- and Age-Induced Leaf Senescence by Reducing ROS Accumulation and Modulating Abscisic Acid and Auxin Biosynthesis in Cucumber Plants”
Claim · model-written summary
Melatonin increased antioxidant capacity and chlorophyll biosynthesis relative to water treatment.
- Taxon
- CucumberCucumis sativust0
- Treatment
- Melatonint0
- Outcome
- antioxidant capacity and chlorophyll biosynthesise0
- Direction
- increasee0
- Comparator
- H2O-treated seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an increase in antioxidant capacity and chlorophyll biosynthesis compared with the H2O-treated seedlings”
t0“Melatonin Positively Regulates Both Dark- and Age-Induced Leaf Senescence by Reducing ROS Accumulation and Modulating Abscisic Acid and Auxin Biosynthesis in Cucumber Plants”
Claim · model-written summary
Melatonin reduced ABA biosynthesis and signaling in greenhouse cucumber.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- Melatonint0
- Outcome
- abscisic acid (ABA) biosynthesis and signaling pathwayse0
- Direction
- reductione0
- Setting
- solar greenhousee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduction in abscisic acid (ABA) biosynthesis and signaling pathways as well as the promotion of auxin (IAA) biosynthesis and signaling pathways in cucumber plants in the solar greenhouse”
t0“Melatonin”
Claim · model-written summary
Melatonin promoted IAA biosynthesis and signaling in greenhouse cucumber.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- Melatonint0
- Outcome
- auxin (IAA) biosynthesis and signaling pathwayse0
- Direction
- promotione0
- Setting
- solar greenhousee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduction in abscisic acid (ABA) biosynthesis and signaling pathways as well as the promotion of auxin (IAA) biosynthesis and signaling pathways in cucumber plants in the solar greenhouse”
t0“Melatonin”
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