Abstract
Root formation is dependent on meristematic activity and is influenced by nitrogen supply. We have previously shown that ubiquitin ligase, EL5, in rice (Oryza sativa) is involved in the maintenance of root meristematic viability. When mutant EL5 protein is overexpressed to dominantly inhibit the endogenous EL5 function in rice, primordial and meristematic necrosis ia observed. Here, we analysed the cause of root cell death in transgenic rice plants (mEL5) overexpressing EL5V162A, which encodes a partly inactive ubiquitin ligase. The mEL5 mutants showed increased sensitivity to nitrogen that was reflected in the inhibition of root formation. Treatment of mEL5 with nitrate or nitrite caused meristematic cell death accompanied by browning. Transcriptome profiling of whole roots exhibited overlaps between nitrite-responsive genes in non-transgenic (NT) rice plants and genes with altered basal expression levels in mEL5. Phytohormone profiling of whole roots revealed that nitrite treatment increased cytokinin levels, but mEL5 constitutively contained more cytokinin than NT plants and showed increased sensitivity to exogenous cytokinin. More superoxide was detected in mEL5 roots after treatment with nitrite or cytokinin, and treatment with an inhibitor of superoxide production prevented mEL5 roots from both nitrite- and cytokinin-induced meristematic cell death. These results indicate a nitrogen-triggered pathway that leads to changes in root formation through the production of cytokinin and superoxide, on which EL5 acts to prevent meristematic cell death.
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Claims 11
Claim · model-written summary
mEL5 mutants had increased nitrogen sensitivity reflected in inhibited root formation.
- Taxon
- rice
Oryza sativat0 - Material
- mEL5 mutantse0
- Gene
- EL5e0
- Outcome
- sensitivity to nitrogene0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mEL5 mutants showed increased sensitivity to nitrogen that was reflected in the inhibition of root formation”
t0“in rice”
Claim · model-written summary
Nitrate treatment caused meristematic cell death and browning in mEL5.
- Taxon
- riceOryza sativat0
- Material
- mEL5e0
- Treatment
- nitratee0
- Outcome
- meristematic cell death accompanied by browninge0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of mEL5 with nitrate or nitrite caused meristematic cell death accompanied by browning”
t0“in rice”
Claim · model-written summary
Nitrite treatment caused meristematic cell death and browning in mEL5.
- Taxon
- riceOryza sativat0
- Material
- mEL5e0
- Treatment
- nitritee0
- Outcome
- meristematic cell death accompanied by browninge0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of mEL5 with nitrate or nitrite caused meristematic cell death accompanied by browning”
t0“in rice”
Claim · model-written summary
mEL5 basal root expression changes overlapped nitrite-responsive genes in nontransgenic rice.
- Taxon
- riceOryza sativae0
- Material
- mEL5e0
- Outcome
- overlaps between nitrite-responsive genese0
- Comparator
- non-transgenic (NT) rice plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transcriptome profiling of whole roots exhibited overlaps between nitrite-responsive genes in non-transgenic (NT) rice plants and genes with altered basal expression levels in mEL5”
Claim · model-written summary
Nitrite increased whole-root cytokinin levels.
- Taxon
- riceOryza sativat0
- Treatment
- nitrite treatmente0
- Outcome
- cytokinin levelse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrite treatment increased cytokinin levels”
t0“in rice”
Claim · model-written summary
mEL5 roots constitutively had more cytokinin than nontransgenic roots.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mEL5 constitutively contained more cytokinin than NT plants”
t0“in rice”
Claim · model-written summary
mEL5 showed increased sensitivity to applied cytokinin.
- Taxon
- riceOryza sativat0
- Material
- mEL5e0
- Treatment
- exogenous cytokinine0
- Outcome
- sensitivitye0
- Direction
- increasede0
- Comparator
- NT plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mEL5 constitutively contained more cytokinin than NT plants and showed increased sensitivity to exogenous cytokinin”
t0“in rice”
Claim · model-written summary
Nitrite produced more superoxide in mEL5 roots.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“More superoxide was detected in mEL5 roots after treatment with nitrite or cytokinin”
t0“in rice”
Claim · model-written summary
Cytokinin produced more superoxide in mEL5 roots.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“More superoxide was detected in mEL5 roots after treatment with nitrite or cytokinin”
t0“in rice”
Claim · model-written summary
Inhibiting superoxide production prevented nitrite-induced meristem death.
- Taxon
- riceOryza sativat0
- Material
- mEL5e0
- Treatment
- an inhibitor of superoxide productione0
- Outcome
- nitrite- and cytokinin-induced meristematic cell deathe0
- Direction
- preventede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“treatment with an inhibitor of superoxide production prevented mEL5 roots from both nitrite- and cytokinin-induced meristematic cell death”
t0“in rice”
Claim · model-written summary
The authors propose that EL5 prevents meristem death in a nitrogen-triggered cytokinin and superoxide pathway.
- Taxon
- riceOryza sativat0
- Gene
- EL5e0
- Outcome
- meristematic cell deathe0
- Qualifier
- production of cytokinin and superoxidee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a nitrogen-triggered pathway that leads to changes in root formation through the production of cytokinin and superoxide, on which EL5 acts to prevent meristematic cell death”
t0“in rice”
The same questions in other papers
nitrogen · cytology · Oryza sativa (rice)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- negative
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class · physiology: oxidative · Oryza sativa (rice)Positive and negative results
2 papers in the same direction as this paper · 6 in the opposite direction
- positive
- positive
- positive
5 papers more in this group
See all 9 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.