Abstract
Cladosporium fulvum is a non-obligate biotrophic fungal pathogen of tomato that belongs to the Dothideomycete class of ascomycete fungi. Ten effector proteins have been cloned from C. fulvum that are classified as avirulence (Avrs: Avr2, Avr4, Avr4E, Avr9) and extracellular proteins (Ecps: Ecp1,
Ecp2, Ecp4, Ecp5, Ecp6, Ecp7), and whose recognition in tomato is mediated by the cognate Cf (for C. fulvum) resistance proteins. Although the interaction between C. fulvum and tomato is regarded as a model for gene-for-gene-based
interactions, so far homologues of the C. fulvum effector proteins have not yet been identified in other fungal pathoghens. By mining sequenced fungal genomes and by using PCR-based techniques we have now identified for the
first time structural and functional homologues of the C. fulvum Avr4, Ecp2 and Ecp6 effectors in other Dothideomycete species, including the devastating pathogen of banana Mycosphaerella fijiensis and the wheat blotch pathogen
Mycosphaerella graminicola. Eight cysteine residues are present in the C. fulvum chitin-binding protein Avr4 that can protect fungal cell-wall chitin against tomato chitinases that accumulate during infection. The cysteine residues and their spacing are also conserved in the Avr4 homologues present in M. fijiensis and other Dothideomycetes, suggesting a similar biological function. Our current studies aim at providing further insight into whether these genes are (i) true homologues shared in ancestors, (ii) have been acquired by horizontal gene
transfer, or (iii) are the result of convergent evolution.
Ecp2, Ecp4, Ecp5, Ecp6, Ecp7), and whose recognition in tomato is mediated by the cognate Cf (for C. fulvum) resistance proteins. Although the interaction between C. fulvum and tomato is regarded as a model for gene-for-gene-based
interactions, so far homologues of the C. fulvum effector proteins have not yet been identified in other fungal pathoghens. By mining sequenced fungal genomes and by using PCR-based techniques we have now identified for the
first time structural and functional homologues of the C. fulvum Avr4, Ecp2 and Ecp6 effectors in other Dothideomycete species, including the devastating pathogen of banana Mycosphaerella fijiensis and the wheat blotch pathogen
Mycosphaerella graminicola. Eight cysteine residues are present in the C. fulvum chitin-binding protein Avr4 that can protect fungal cell-wall chitin against tomato chitinases that accumulate during infection. The cysteine residues and their spacing are also conserved in the Avr4 homologues present in M. fijiensis and other Dothideomycetes, suggesting a similar biological function. Our current studies aim at providing further insight into whether these genes are (i) true homologues shared in ancestors, (ii) have been acquired by horizontal gene
transfer, or (iii) are the result of convergent evolution.
| Original language | English |
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| Title of host publication | ISMPMI International Congress abstracts, Quebec City, Canada, 19-23 July 2009 |
| Publisher | International Society for Molecular Plant-Microbe Interactions |
| Publication status | Published - 2009 |
| Event | XIV International Congress on Molecular Plant-Microbe Interactions, Quebec City, Canada - Duration: 19 Jul 2009 → 23 Jul 2009 |
Conference/symposium
| Conference/symposium | XIV International Congress on Molecular Plant-Microbe Interactions, Quebec City, Canada |
|---|---|
| Period | 19/07/09 → 23/07/09 |