Abstract
Phytochrome regulates lettuce (Lactuca sativa L. cv. Grand Rapids) seed germination via the control of the endogenous level of bioactive gibberellin (GA). In addition to the previously identified LsGA20ox1, LsGA20ox2, LsGA3ox1, LsGA3ox2, LsGA2ox1, and LsGA2ox2, five cDNAs were isolated from lettuce seeds: LsCPS, LsKS, LsKO1, LsKO2, and LsKAO. Using an Escherichia coli expression system and functional assays, it is shown that LsCPS and LsKS encode ent-copalyl diphosphate synthase and ent-kaurene synthase, respectively. Using a Pichia pastoris system, it was found that LsKO1 and LsKO2 encode ent-kaurene oxidases and LsKAO encodes ent-kaurenoic acid oxidase. A comprehensive expression analysis of GA metabolism genes using the quantitative reverse transcription polymerase chain reaction suggested that transcripts of LsGA3ox1 and LsGA3ox2, both of which encode GA 3-oxidase for GA activation, were primarily expressed in the hypocotyl end of lettuce seeds, were expressed at much lower levels than the other genes tested, and were potently up-regulated by phytochrome. Furthermore, LsDELLA1 and LsDELLA2 cDNAs that encode DELLA proteins, which act as negative regulators in the GA signalling pathway, were isolated from lettuce seeds. The transcript levels of these two genes were little affected by light. Lettuce seeds in which de novo GA biosynthesis was suppressed responded almost identically to exogenously applied GA, irrespective of the light conditions, suggesting that GA responsiveness is not significantly affected by light in lettuce seeds. It is proposed that lettuce seed germination is regulated mainly via the control of the endogenous content of bioactive GA, rather than the control of GA responsiveness.
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Claims 11
Claim · model-written summary
Five GA pathway cDNAs were isolated from lettuce seeds.
- Taxon
- lettuce
Lactuca sativae0 - Gene
- LsCPS, LsKS, LsKO1, LsKO2, and LsKAOe0
- Outcome
- five cDNAs were isolatede0
- Value
- five cDNAse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“five cDNAs were isolated from lettuce seeds: LsCPS, LsKS, LsKO1, LsKO2, and LsKAO.”
Claim · model-written summary
LsCPS and LsKS encoded ent-copalyl diphosphate synthase and ent-kaurene synthase, respectively.
- Taxon
- lettuceLactuca sativat0
- Gene
- LsCPS and LsKSe0
- Outcome
- encode ent-copalyl diphosphate synthase and ent-kaurene synthasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“LsCPS and LsKS encode ent-copalyl diphosphate synthase and ent-kaurene synthase, respectively.”
t0“lettuce”
Claim · model-written summary
LsKO1 and LsKO2 encoded ent-kaurene oxidases.
- Taxon
- lettuceLactuca sativat0
- Gene
- LsKO1 and LsKO2e0
- Outcome
- encode ent-kaurene oxidasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“LsKO1 and LsKO2 encode ent-kaurene oxidases”
t0“lettuce”
Claim · model-written summary
LsKAO encoded ent-kaurenoic acid oxidase.
- Taxon
- lettuceLactuca sativat0
- Gene
- LsKAOe0
- Outcome
- encodes ent-kaurenoic acid oxidasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“LsKAO encodes ent-kaurenoic acid oxidase.”
t0“lettuce”
Claim · model-written summary
LsGA3ox1 and LsGA3ox2 transcripts were primarily expressed at the hypocotyl end of lettuce seeds.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- hypocotyl end of lettuce seedse0
- Gene
- LsGA3ox1 and LsGA3ox2e0
- Outcome
- transcripts of LsGA3ox1 and LsGA3ox2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transcripts of LsGA3ox1 and LsGA3ox2, both of which encode GA 3-oxidase for GA activation, were primarily expressed in the hypocotyl end of lettuce seeds”
Claim · model-written summary
LsGA3ox1 and LsGA3ox2 expression was much lower than that of other tested genes.
- Taxon
- lettuceLactuca sativat0
- Gene
- LsGA3ox1 and LsGA3ox2e1
- Outcome
- expressede0
- Direction
- much lowere0
- Comparator
- other genes testede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“were expressed at much lower levels than the other genes tested”
t0“lettuce”
e1“transcripts of LsGA3ox1 and LsGA3ox2, both of which encode GA 3-oxidase for GA activation”
Claim · model-written summary
Phytochrome strongly up-regulated LsGA3ox1 and LsGA3ox2 transcripts.
- Taxon
- lettuceLactuca sativat0
- Gene
- LsGA3ox1 and LsGA3ox2e1
- Outcome
- potently up-regulatede0
- Qualifier
- phytochromee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“were potently up-regulated by phytochrome.”
t0“lettuce”
e1“transcripts of LsGA3ox1 and LsGA3ox2, both of which encode GA 3-oxidase for GA activation”
Claim · model-written summary
LsDELLA1 and LsDELLA2 cDNAs were isolated from lettuce seeds.
- Taxon
- lettuceLactuca sativae0
- Gene
- LsDELLA1 and LsDELLA2e0
- Outcome
- cDNAs that encode DELLA proteinse0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“LsDELLA1 and LsDELLA2 cDNAs that encode DELLA proteins, which act as negative regulators in the GA signalling pathway, were isolated from lettuce seeds.”
Claim · model-written summary
Light had little effect on LsDELLA1 and LsDELLA2 transcript levels.
- Taxon
- lettuceLactuca sativat0
- Treatment
- lighte0
- Gene
- LsDELLA1 and LsDELLA2e1
- Outcome
- transcript levelse0
- Direction
- little affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The transcript levels of these two genes were little affected by light.”
t0“lettuce”
e1“LsDELLA1 and LsDELLA2 cDNAs”
Claim · model-written summary
GA-suppressed lettuce seeds responded almost identically to applied GA regardless of light conditions.
- Taxon
- LettuceLactuca sativae0
- Organ / stage
- seedse0
- Treatment
- exogenously applied GAe0
- Outcome
- responded almost identicallye0
- Direction
- almost identicallye0
- Comparator
- light conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lettuce seeds in which de novo GA biosynthesis was suppressed responded almost identically to exogenously applied GA, irrespective of the light conditions”
Claim · model-written summary
The authors propose that endogenous bioactive GA content chiefly regulates lettuce seed germination.
- Taxon
- lettuceLactuca sativae0
- Outcome
- seed germinatione0
- Qualifier
- control of the endogenous content of bioactive GAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lettuce seed germination is regulated mainly via the control of the endogenous content of bioactive GA, rather than the control of GA responsiveness.”
The same questions in other papers
light · molecular: expression · Lactuca sativa (garden lettuce)Positive and negative results
2 papers in the same direction as this paper · 9 in the opposite direction
- no effect
- positive
- positive
8 papers more in this group
See all 12 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.