Abstract
Plants challenged by pathogens, especially necrotrophic fungi such as Botrytis cinerea, produce high levels of ethylene. At present, the signaling pathways underlying the induction of ethylene after pathogen infection are largely unknown. MPK6, an Arabidopsis stress-responsive mitogen-activated protein kinase (MAPK) was previously shown to regulate the stability of ACS2 and ACS6, two type I ACS isozymes (1-amino-cyclopropane-1-carboxylic acid synthase). Phosphorylation of ACS2 and ACS6 by MPK6 prevents rapid degradation of ACS2/ACS6 by the 26S proteasome pathway, resulting in an increase in cellular ACS activity and ethylene biosynthesis. Here, we show that MPK3, which shares high homology and common upstream MAPK kinases with MPK6, is also capable of phosphorylating ACS2 and ACS6. In the mpk3 mutant background, ethylene production in gain-of-function GVG-NtMEK2(DD) transgenic plants was compromised, suggesting that MPK6 and MPK3 function together to stabilize ACS2 and ACS6. Using a liquid-cultured seedling system, we found that B. cinerea-induced ethylene biosynthesis was greatly compromised in mpk3/mpk6 double mutant seedlings. In contrast, ethylene production decreased only slightly in the mpk6 single mutant and not at all in the mpk3 single mutant, demonstrating overlapping roles for these two highly homologous MAPKs in pathogen-induced ethylene induction. Consistent with the role of MPK3/MPK6 in the process, mutation of ACS2 and ACS6, two genes encoding downstream substrates of MPK3/MPK6, also reduced B. cinerea-induced ethylene production. The residual levels of ethylene induction in the acs2/acs6 double mutant suggest the involvement of additional ACS isoforms, possibly regulated by MAPK-independent pathway(s).
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Claims 7
Claim · model-written summary
MPK3 phosphorylated ACS2 and ACS6.
- Taxon
- Arabidopsis
Arabidopsist0 - Gene
- MPK3e0
- Outcome
- phosphorylating ACS2 and ACS6e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MPK3, which shares high homology and common upstream MAPK kinases with MPK6, is also capable of phosphorylating ACS2 and ACS6”
t0“Arabidopsis”
Claim · model-written summary
The mpk3 mutation compromised ethylene production in GVG-NtMEK2(DD) transgenic plants.
- Taxon
- ArabidopsisArabidopsist0
- Material
- mpk3e0
- Treatment
- mpk3 mutant backgrounde0
- Outcome
- ethylene productione0
- Direction
- compromisede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the mpk3 mutant background, ethylene production in gain-of-function GVG-NtMEK2(DD) transgenic plants was compromised”
t0“Arabidopsis”
Claim · model-written summary
Botrytis-induced ethylene biosynthesis was greatly compromised in mpk3/mpk6 double mutant seedlings.
- Taxon
- ArabidopsisArabidopsist0
- Material
- mpk3/mpk6 double mutante0
- Treatment
- B. cinerea-inducede0
- Interactor
- Botrytis cinerea
Botrytis cinereae1pathogen - Outcome
- ethylene biosynthesise0
- Direction
- compromisede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“B. cinerea-induced ethylene biosynthesis was greatly compromised in mpk3/mpk6 double mutant seedlings”
e1“Botrytis cinerea”
t0“Arabidopsis”
Claim · model-written summary
Ethylene production decreased slightly in mpk6 single mutants.
- Taxon
- ArabidopsisArabidopsist0
- Material
- mpk6 single mutante0
- Treatment
- mpk6 single mutante0
- Interactor
- Botrytis cinereaBotrytis cinereae1pathogen
- Outcome
- ethylene productione0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ethylene production decreased only slightly in the mpk6 single mutant”
t0“Arabidopsis”
e1“Botrytis cinerea”
Claim · model-written summary
Ethylene production did not decrease in mpk3 single mutants.
- Taxon
- ArabidopsisArabidopsist0
- Material
- mpk3 single mutante0
- Treatment
- mpk3 single mutante0
- Interactor
- Botrytis cinereaBotrytis cinereae2pathogen
- Outcome
- ethylene productione1
- Direction
- not at alle0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“not at all in the mpk3 single mutant”
e1“ethylene production decreased only slightly in the mpk6 single mutant”
t0“Arabidopsis”
e2“Botrytis cinerea”
Claim · model-written summary
ACS2 and ACS6 mutation reduced Botrytis-induced ethylene production.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mutation of ACS2 and ACS6e0
- Interactor
- Botrytis cinereaBotrytis cinereae1pathogen
- Outcome
- B. cinerea-induced ethylene productione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mutation of ACS2 and ACS6, two genes encoding downstream substrates of MPK3/MPK6, also reduced B. cinerea-induced ethylene production”
t0“Arabidopsis”
e1“Botrytis cinerea”
Claim · model-written summary
Residual ethylene induction in acs2/acs6 suggests additional ACS isoforms may contribute.
- Taxon
- ArabidopsisArabidopsist0
- Material
- acs2/acs6 double mutante0
- Gene
- additional ACS isoformse0
- Outcome
- residual levels of ethylene inductione0
- Qualifier
- possibly regulated by MAPK-independent pathway(s)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The residual levels of ethylene induction in the acs2/acs6 double mutant suggest the involvement of additional ACS isoforms, possibly regulated by MAPK-independent pathway(s).”
t0“Arabidopsis”
The same questions in other papers
loss of function · Botrytis cinerea · ArabidopsisPositive and negative results
15 papers in the same direction as this paper · 4 in the opposite direction
- negative
- positive
- positive
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See all 20 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.