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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2002-2-21
pubmed:databankReference
pubmed:abstractText
The growth of the biotrophic pathogen Cladosporium fulvum within the tomato (Lycopersicon esculentum Mill.) leaf is restricted to the intercellular space. Previous studies from this laboratory have demonstrated that gamma-aminobutyric acid (GABA) accumulates to millimolar concentrations in the apoplast during a compatible interaction. We decided to further investigate the role of GABA during infection. A gene encoding a required enzyme for GABA metabolism, GABA transaminase (Gat1), was cloned and sequenced from C. fulvum. The predicted protein sequence of Gat1 had high homology to other fungal GABA transaminases, particularly from Aspergillus nidulans. In vitro expression experiments revealed Gat1 to be strongly expressed during fungal growth on both GABA and glutamate whereas nearly no expression was evident during nitrogen starvation conditions. Expression of Gat1 was also apparent during infection, suggesting for the first time that C. fulvum actively metabolises GABA during infection. This indicates that the fungus may be utilising the GABA in the apoplast as a nutrient source. Further analysis revealed that the expression of tomato glutamate decarboxylase, the enzyme responsible for GABA synthesis, appeared appreciably higher during a compatible interaction than in the incompatible interaction. These findings imply that the infecting fungus may alter the physiology of the tomato leaf with the result that a source of nitrogen is supplied.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
214
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
414-20
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Evidence that gamma-aminobutyric acid is a major nitrogen source during Cladosporium fulvum infection of tomato.
pubmed:affiliation
Department of Physiology, Carlsberg Laboratory, Copenhagen Valby, Denmark.
pubmed:publicationType
Journal Article