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Protein Polyubiquitination Plays a Role in Basal Host Resistance of Barley
- Source :
- The Plant Cell. 18:3321-3331
- Publication Year :
- 2006
- Publisher :
- Oxford University Press (OUP), 2006.
-
Abstract
- To study protein ubiquitination pathways in the interaction of barley (Hordeum vulgare) with the powdery mildew fungus (Blumeria graminis), we measured protein turnover and performed transient-induced gene silencing (TIGS) of ubiquitin and 26S proteasome subunit encoding genes in epidermal cells. Attack by B. graminis hyperdestabilized a novel unstable green fluorescent protein fusion that contains a destabilization domain of a putative barley 1-aminocyclopropane-1-carboxylate synthase, suggesting enhanced protein turnover. Partial depletion of cellular ubiquitin levels by TIGS induced extreme susceptibility of transformed cells toward the appropriate host pathogen B. graminis f. sp hordei, whereas papilla-based resistance to the nonhost pathogen B. graminis f. sp tritici and host resistance mediated by the mlo gene (for mildew resistance locus O) remained unaffected. Cells were rescued from TIGS-induced ubiquitin depletion by synthetic genes encoding wild-type or mutant barley monoubiquitin proteins. The strongest rescue was from a gene encoding a K63R mutant form of ubiquitin blocked in several ubiquitination pathways while still allowing Lys-48–dependent polyubiquitination required for proteasomal protein degradation. Systematic RNA interference of 40 genes encoding all 17 subunits of the proteasome 19S regulatory particle failed to induce hypersusceptibility against B. graminis f. sp hordei. This suggests a role for Lys-48–linked protein polyubiquitination, which is independent from the proteasome pathway, in basal host defense of barley.
- Subjects :
- Proteasome Endopeptidase Complex
Time Factors
Recombinant Fusion Proteins
Protein subunit
Green Fluorescent Proteins
Molecular Sequence Data
Gene Expression
Lyases
Blumeria graminis
Protein polyubiquitination
Plant Science
Protein degradation
Genes, Plant
Models, Biological
Plant Epidermis
Ascomycota
Ubiquitin
Genes, Reporter
Gene Silencing
Polyubiquitin
Research Articles
Triticum
Plant Diseases
Plant Proteins
Genetics
biology
Lysine
food and beverages
Hordeum
Cell Biology
biology.organism_classification
Immunity, Innate
Protein ubiquitination
Protein Structure, Tertiary
Cell biology
Plant Leaves
Protein Subunits
Proteasome
biology.protein
Hordeum vulgare
Subjects
Details
- ISSN :
- 1532298X
- Volume :
- 18
- Database :
- OpenAIRE
- Journal :
- The Plant Cell
- Accession number :
- edsair.doi.dedup.....84a08a56c23057cfa65e488f963e15c2