Cladosporium

About: Cladosporium is a research topic. Over the lifetime, 2777 publications have been published within this topic receiving 59099 citations.

Isolation of the tomato Cf-9 gene for resistance to Cladosporium fulvum by transposon tagging

Abstract: The tomato Cf-9 gene confers resistance to infection by races of the fungus Cladosporium fulvum that carry the avirulence gene Avr9. The Cf-9 gene was isolated by transposon tagging with the maize transposable element Dissociation. The DNA sequence of Cf-9 encodes a putative membrane-anchored extracytoplasmic glycoprotein. The predicted protein shows homology to the receptor domain of several receptor-like protein kinases in Arabidopsis, to antifungal polygalacturonase-inhibiting proteins in plants, and to other members of the leucine-rich repeat family of proteins. This structure is consistent with that of a receptor that could bind Avr9 peptide and activate plant defense.

Cladosporium Avr2 inhibits tomato Rcr3 protease required for Cf-2-dependent disease resistance.

Abstract: How plants recognize pathogens and activate defense is still mysterious. Direct interaction between pathogen avirulence (Avr) proteins and plant disease resistance proteins is the exception rather than the rule. During infection, Cladosporium fulvum secretes Avr2 protein into the apoplast of tomato leaves and, in the presence of the extracellular leucine-rich repeat receptor-like Cf-2 protein, triggers a hypersensitive response (HR) that also requires the extracellular tomato cysteine protease Rcr3. We show here that Avr2 binds and inhibits Rcr3 and propose that the Rcr3-Avr2 complex enables the Cf-2 protein to activate an HR.

Indoor airborne fungal spores, house dampness and associations with environmental factors and respiratory health in children

Abstract: Background Children living in a damp house are more likely to suffer from respiratory symptoms and it has been suggested that exposure to fungi is an important contributing factor. However, more knowledge about underlying mechanisms for the association are needed. Objective To identify associations between measures of house dampness, levels of airborne fungal spores, housing factors and health outcomes in children. Methods Eighty households with 148 children between 7 and 14 years of age were recruited in the Latrobe Valley, Victoria, Australia. Some 36% of participating children were asthmatic. Six sampling visits were made to each house between March 1994 and February 1995 on a 2-monthly cycle. Samples for airborne total and viable fungal spores were collected from bedrooms, living rooms, kitchens and outdoors. A detailed dwelling characterization, using a questionnaire and inspection surveys, was carried out. Skin-prick tests were performed with extracts of common aeroallergens and a respiratory questionnaire was completed for each child. Results Large airborne fungal spore concentrations were recorded in association with: musty odour, water intrusion, high indoor humidity, limited ventilation through open windows, few extractor fans and failure to remove indoor mould growth. Visible mould growth or condensation evidence was associated with large concentrationsof Cladosporium spores, but not with large total spore concentrations. Penicillium exposure was a risk factor for asthma, while Aspergillus exposure was a risk factor for atopy. Fungal allergies were more common among children exposed to Cladosporium or Penicillium in winter or to musty odour. Respiratory symptoms were marginally more common with exposure to Cladosporium or total spores in winter. Conclusion Indoor exposure to certain fungal genera in winter was a risk factor for asthma, atopy and respiratory symptoms in children. On the other hand, no significant associations were seen between average viable or total spore concentrations and child health. Actual measurements of fungal spores predict health outcomes better than reported dampness.

Cladosporium fulvum Avr4 protects fungal cell walls against hydrolysis by plant chitinases accumulating during infection

Abstract: Resistance against the leaf mold fungus Cladosporium fulvum is mediated by the tomato Cf proteins which belong to the class of receptor-like proteins and indirectly recognize extracellular avirulence proteins (Avrs) of the fungus. Apart from triggering disease resistance, Avrs are believed to play a role in pathogenicity or virulence of C. fulvum. Here, we report on the avirulence protein Avr4, which is a chitin-binding lectin containing an invertebrate chitin-binding domain (CBM14). This domain is found in many eukaryotes, but has not yet been described in fungal or plant genomes. We found that interaction of Avr4 with chitin is specific, because it does not interact with other cell wall polysaccharides. Avr4 binds to chitin oligomers with a minimal length of three N-acetyl glucosamine residues. In vitro, Avr4 protects chitin against hydrolysis by plant chitinases. Avr4 also binds to chitin in cell walls of the fungi Trichoderma viride and Fusarium solani f. sp. phaseoli and protects these fungi against normally deleterious concentrations of plant chitinases. In situ fluorescence studies showed that Avr4 also binds to cell walls of C. fulvum during infection of tomato, where it most likely protects the fungus against tomato chitinases, suggesting that Avr4 is a counter-defensive virulence factor.