Abstract
Melatonin plays a crucial role in regulating plant cold tolerance, but the mechanisms underlying signal transduction remain elusive. In this study, we discovered that overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance, accompanied by the accumulation of cytosolic free calcium ([Ca2+]cyt), a stimulation of Ca2+ influx, and upregulation of 4 Ca2+-permeable channel genes (CNGC2/10/17/20). Conversely, the knockout of COMT1 exhibited contrasting effects compared with its overexpression. Knocking out the 4 CNGC genes revealed that only cyclic nucleotide-gated ion channel 20 (CNGC20) mediates melatonin-induced Ca2+ influx in response to cold stimuli. CNGC20 deletion impeded watermelon callus redifferentiation, prompting us to employ a virus-induced gene silencing strategy to suppress its expression. Silencing CNGC20 compromised COMT1 overexpression-induced [Ca2+]cyt accumulation, Ca2+ influx, and watermelon cold tolerance. Yeast 2-hybrid, bimolecular fluorescence complementation, firefly luciferase complementation imaging, and pull-down assays revealed an interaction between CNGC20 and calmodulin7 (CaM7). Overexpressing CaM7 inhibited melatonin-induced [Ca2+]cyt accumulation, Ca2+ influx, and watermelon cold tolerance. Conversely, silencing CaM7 increased [Ca2+]cyt accumulation, Ca2+ influx, and cold tolerance, whereas COMT1 overexpression failed to further enhance these responses in CaM7-silenced plants, indicating the negative regulation role of CaM7 in melatonin-mediated cold responses. Overall, these findings provide insights into the molecular mechanisms underlying melatonin-enhanced plant cold tolerance via Ca2+ signaling, holding potential for breeding/engineering cold-tolerant cucurbit varieties.
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Claims 13
Claim · model-written summary
COMT1 overexpression enhanced watermelon cold tolerance
- Taxon
- watermelon
Citrullus lanatuse1 - Treatment
- overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1)e1
- Gene
- caffeic acid O-methyltransferase1 (COMT1)e1
- Outcome
- cold tolerancee1
- Direction
- enhancede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance, accompanied by the accumulation of cytosolic free calcium ([Ca2+]cyt), a stimulation of Ca2+ influx, and upregulation of 4 Ca2+-permeable channel genes (CNGC2/10/17/20)”
Claim · model-written summary
COMT1 overexpression was accompanied by accumulation of cytosolic free calcium in watermelon
- Taxon
- watermelonCitrullus lanatuse1
- Treatment
- overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1)e1
- Outcome
- accumulation of cytosolic free calciume1
- Direction
- increaseinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance, accompanied by the accumulation of cytosolic free calcium ([Ca2+]cyt), a stimulation of Ca2+ influx, and upregulation of 4 Ca2+-permeable channel genes (CNGC2/10/17/20)”
Claim · model-written summary
COMT1 overexpression stimulated Ca2+ influx in watermelon
- Taxon
- watermelonCitrullus lanatuse1
- Treatment
- overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1)e1
- Outcome
- Ca2+ influxe1
- Direction
- increaseinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance, accompanied by the accumulation of cytosolic free calcium ([Ca2+]cyt), a stimulation of Ca2+ influx, and upregulation of 4 Ca2+-permeable channel genes (CNGC2/10/17/20)”
Claim · model-written summary
COMT1 overexpression upregulated four Ca2+-permeable channel genes (CNGC2, CNGC10, CNGC17, CNGC20) in watermelon
- Taxon
- watermelonCitrullus lanatuse1
- Treatment
- overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1)e1
- Gene
- CNGC2/10/17/20e1
- Outcome
- Ca2+-permeable channel genese1
- Direction
- upregulatione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance, accompanied by the accumulation of cytosolic free calcium ([Ca2+]cyt), a stimulation of Ca2+ influx, and upregulation of 4 Ca2+-permeable channel genes (CNGC2/10/17/20)”
Claim · model-written summary
Knockout of COMT1 had contrasting effects compared with its overexpression
- Taxon
- watermelonCitrullus lanatuse1
- Treatment
- knockout of COMT1e2
- Outcome
- contrasting effectse2
- Comparator
- its overexpressione2
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance”
e2“Conversely, the knockout of COMT1 exhibited contrasting effects compared with its overexpression”
Claim · model-written summary
Only CNGC20 among the four CNGC genes mediates melatonin-induced Ca2+ influx in response to cold
- Taxon
- watermelonCitrullus lanatuse1
- Gene
- cyclic nucleotide-gated ion channel 20 (CNGC20)e3
- Outcome
- melatonin-induced Ca2+ influxe3
- Qualifier
- in response to cold stimulie3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance”
e3“Knocking out the 4 CNGC genes revealed that only cyclic nucleotide-gated ion channel 20 (CNGC20) mediates melatonin-induced Ca2+ influx in response to cold stimuli”
Claim · model-written summary
CNGC20 deletion impeded watermelon callus redifferentiation
- Taxon
- watermelonCitrullus lanatuse4
- Organ / stage
- calluse4
- Treatment
- CNGC20 deletione4
- Gene
- CNGC20e4
- Outcome
- callus redifferentiatione4
- Direction
- impedede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“CNGC20 deletion impeded watermelon callus redifferentiation”
Claim · model-written summary
Silencing CNGC20 compromised COMT1 overexpression-induced Ca2+ accumulation, Ca2+ influx and cold tolerance in watermelon
- Taxon
- watermelonCitrullus lanatuse5
- Treatment
- Silencing CNGC20e5
- Gene
- CNGC20e5
- Outcome
- [Ca2+]cyt accumulation, Ca2+ influx, and watermelon cold tolerancee5
- Direction
- compromisede5
- Comparator
- COMT1 overexpressione5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Silencing CNGC20 compromised COMT1 overexpression-induced [Ca2+]cyt accumulation, Ca2+ influx, and watermelon cold tolerance”
Claim · model-written summary
CNGC20 and calmodulin7 (CaM7) interact
- Taxon
- watermelonCitrullus lanatuse1
- Gene
- CNGC20 and calmodulin7 (CaM7)e6
- Outcome
- an interactione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance”
e6“Yeast 2-hybrid, bimolecular fluorescence complementation, firefly luciferase complementation imaging, and pull-down assays revealed an interaction between CNGC20 and calmodulin7 (CaM7)”
Claim · model-written summary
Overexpressing CaM7 inhibited melatonin-induced Ca2+ accumulation, Ca2+ influx and cold tolerance in watermelon
- Taxon
- watermelonCitrullus lanatuse7
- Treatment
- Overexpressing CaM7e7
- Gene
- CaM7e7
- Outcome
- melatonin-induced [Ca2+]cyt accumulation, Ca2+ influx, and watermelon cold tolerancee7
- Direction
- inhibitede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“Overexpressing CaM7 inhibited melatonin-induced [Ca2+]cyt accumulation, Ca2+ influx, and watermelon cold tolerance”
Claim · model-written summary
Silencing CaM7 increased Ca2+ accumulation, Ca2+ influx and cold tolerance
- Taxon
- watermelonCitrullus lanatuse1
- Treatment
- silencing CaM7e2
- Gene
- CaM7e2
- Outcome
- [Ca2+]cyt accumulation, Ca2+ influx, and cold tolerancee2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance”
e2“Conversely, silencing CaM7 increased [Ca2+]cyt accumulation, Ca2+ influx, and cold tolerance”
Claim · model-written summary
COMT1 overexpression failed to further enhance cold responses in CaM7-silenced watermelon
- Taxon
- watermelonCitrullus lanatuse1
- Treatment
- COMT1 overexpressione2
- Outcome
- these responsese2
- Direction
- failed to further enhancee2
- Comparator
- CaM7-silenced plantse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance”
e2“COMT1 overexpression failed to further enhance these responses in CaM7-silenced plants”
Claim · model-written summary
CaM7 negatively regulates melatonin-mediated cold responses
- Taxon
- watermelonCitrullus lanatuse1
- Gene
- CaM7e2
- Outcome
- melatonin-mediated cold responsese2
- Qualifier
- negative regulation rolee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“overexpression of the melatonin biosynthetic gene caffeic acid O-methyltransferase1 (COMT1) enhanced watermelon (Citrullus lanatus) cold tolerance”
e2“indicating the negative regulation role of CaM7 in melatonin-mediated cold responses”
The same questions in other papers
loss of function · growth · Citrullus lanatus (watermelon)Results agree
1 paper in the same direction as this paper
- negative
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.