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Dominant-negative interference with defence signalling by truncation mutations of the tomato Cf-9 disease resistance gene.
- Source :
-
The Plant journal : for cell and molecular biology [Plant J] 2006 May; Vol. 46 (3), pp. 385-99. - Publication Year :
- 2006
-
Abstract
- The tomato Cf-9 gene confers resistance to races of the leaf mould fungus Cladosporium fulvum that carry the Avr9 avirulence gene. Cf-9 was isolated by transposon tagging using a modified maize Dissociation (Ds) element. This generated an allelic series of Ds-induced mutations of Cf-9, of which two were found to confer novel phenotypes in a screen for mutants affecting wild-type Cf-9 function in trans. Genetic and molecular analysis of these mutants suggested semidominant, Avr9-dependent, negative-interfering mutations involving Ds insertions in a defined subregion of Cf-9. Interference was associated with expression of the 5'-end of Cf-9 upstream of the Ds insertions in these mutants, suggesting that truncated Cf-9 proteins were the likely cause of interference. Transgenic tomato lines harbouring Cf-9 constructs with premature stop codons in positions similar to the Ds insertions also showed interference, indicating that the presence of Ds was not required for interference to occur. Interestingly, interference in these transgenic lines was completely dominant and was associated with a pronounced developmental phenotype that was dependent on co-expression of Cf-9, Avr9 and a truncated Cf-9 transgene. However, interference with a weakly autoactive Hcr9 gene was Avr9-independent and did not cause a developmental phenotype, suggesting that localized restoration of Cf-9/Avr9-dependent cell death was responsible for the developmental phenotype. The restricted region in which truncation of Cf-9 results in dominant-negative interference suggests that leucine-rich repeats (LRR) 16-19 of Cf-9 may mediate dimerization of Cf-9 and LRRs 20-23 may mediate interactions with downstream partner proteins required for Cf-9 signalling, or vice versa.
- Subjects :
- Amino Acid Motifs
Amino Acid Sequence
Cladosporium pathogenicity
Codon, Nonsense
Fungal Proteins genetics
Immunity, Innate
Solanum lycopersicum anatomy & histology
Solanum lycopersicum microbiology
Membrane Glycoproteins chemistry
Membrane Glycoproteins metabolism
Molecular Sequence Data
Mutagenesis, Insertional
Phenotype
Plant Proteins chemistry
Plant Proteins metabolism
Plants, Genetically Modified metabolism
Sequence Deletion
Signal Transduction
Solanum lycopersicum genetics
Membrane Glycoproteins genetics
Plant Proteins genetics
Subjects
Details
- Language :
- English
- ISSN :
- 0960-7412
- Volume :
- 46
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The Plant journal : for cell and molecular biology
- Publication Type :
- Academic Journal
- Accession number :
- 16623900
- Full Text :
- https://doi.org/10.1111/j.1365-313X.2006.02699.x