Abstract
The active defense of plants against pathogens often includes rapid and localized cell death known as hypersensitive response (HR). Protein phosphorylation and dephosphorylation are implicated in this event based on studies using protein kinase and phosphatase inhibitors. Recent transient gain-of-function studies demonstrated that the activation of salicylic acid-induced protein kinase (SIPK) and wounding-induced protein kinase (WIPK), two tobacco mitogen-activated protein kinases (MAPKs) by their upstream MAPK kinase (MAPKK), NtMEK2 leads to HR-like cell death. Here, we report that the conserved kinase interaction motif (KIM) in MAPKKs is required for NtMEK2 function. Mutation of the conserved basic amino acids in this motif, or the deletion of N-terminal 64 amino acids containing this motif significantly compromised or abolished the ability of NtMEK2DD to activate SIPK/WIPK in vivo. These mutants were also defective in interacting with SIPK and WIPK, suggesting protein-protein interaction is required for the functional integrity of this MAPK cascade. To eliminate Agrobacterium that is known to activate a number of defense responses in transient transformation experiments, we generated permanent transgenic plants. Induction of NtMEK2DD expression by dexamethasone induced HR-like cell death in both T1 and T2 plants. In addition, by using PVX-induced gene silencing, we demonstrated that the suppression of all three known components in the NtMEK2-SIPK/WIPK pathway attenuated N gene-mediated TMV resistance. Together with previous report that SIPK and WIPK are activated by TMV in a gene-for-gene-dependent manner, we conclude that NtMEK2-SIPK/WIPK pathway plays a positive role in N gene-mediated resistance, possibly through regulating HR cell death.
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Claims 5
Claim · model-written summary
Mutation of the kinase interaction motif compromised or abolished NtMEK2DD activation of SIPK/WIPK in tobacco.
- Taxon
- tobacco
Nicotiana tabacumt0 - Treatment
- Mutation of the conserved basic amino acids in this motife0
- Gene
- NtMEK2DDe0
- Outcome
- ability of NtMEK2DD to activate SIPK/WIPKe0
- Direction
- compromised or abolishede0
Not reportedOrgan / stageComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mutation of the conserved basic amino acids in this motif, or the deletion of N-terminal 64 amino acids containing this motif significantly compromised or abolished the ability of NtMEK2DD to activate SIPK/WIPK in vivo”
t0“tobacco”
Claim · model-written summary
Deletion of the N-terminal 64 amino acids compromised or abolished NtMEK2DD activation of SIPK/WIPK.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- the deletion of N-terminal 64 amino acids containing this motife0
- Gene
- NtMEK2DDe0
- Outcome
- ability of NtMEK2DD to activate SIPK/WIPKe0
- Direction
- compromised or abolishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the deletion of N-terminal 64 amino acids containing this motif significantly compromised or abolished the ability of NtMEK2DD to activate SIPK/WIPK in vivo”
t0“tobacco”
Claim · model-written summary
The motif mutants were defective in interacting with SIPK and WIPK.
- Taxon
- tobaccoNicotiana tabacumt0
- Gene
- SIPK and WIPKe0
- Outcome
- defective in interacting with SIPK and WIPKe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These mutants were also defective in interacting with SIPK and WIPK”
t0“tobacco”
Claim · model-written summary
Dexamethasone induction of NtMEK2DD caused HR-like cell death in T1 and T2 transgenic tobacco plants.
- Taxon
- tobaccoNicotiana tabacumt0
- Material
- T1 and T2 plantse0
- Treatment
- dexamethasonee0
- Gene
- NtMEK2DDe0
- Outcome
- HR-like cell deathe0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Induction of NtMEK2DD expression by dexamethasone induced HR-like cell death in both T1 and T2 plants”
t0“tobacco”
Claim · model-written summary
Silencing components of the NtMEK2-SIPK/WIPK pathway attenuated N gene-mediated TMV resistance.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- suppression of all three known components in the NtMEK2-SIPK/WIPK pathwaye0
- Interactor
- TMV
Tobacco mosaic viruse0pathogen - Gene
- NtMEK2-SIPK/WIPKe0
- Outcome
- N gene-mediated TMV resistancee0
- Direction
- attenuatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“suppression of all three known components in the NtMEK2-SIPK/WIPK pathway attenuated N gene-mediated TMV resistance”
t0“tobacco”
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