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The fungal pathogen Cochliobolus heterostrophus responds to maize phenolics: novel small molecule signals in a plant-fungal interaction

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Title The fungal pathogen Cochliobolus heterostrophus
responds to maize phenolics: novel small molecule
signals in a plant-fungal interaction
 
Creator Shanmugam, V
Ronen, M
Shalaby, S
Larkov, O
Rachamim, Y
Hader, R
Rose, M S
Carmeli, S
Horwitz, B A
Lev, S
 
Description The transcription factor ChAP1 of the fungal
pathogen of maize, Cochliobolus heterostrophus,
responds to oxidative stress by migration to the
nucleus and activation of antioxidant genes. Phenolic
and related compounds found naturally in
the host also trigger nuclear localization of ChAP1,
but only slight upregulation of some antioxidant
genes. ChAP1 thus senses phenolic compounds
without triggering a strong antioxidant response.
We therefore searched for genes whose expression
is regulated by phenolic compounds and/or
ChAP1. The C. heterostrophus genome contains a
cluster of genes for metabolism of phenolics. One
such gene, catechol dioxygenase CCHD1, was
induced at least 10-fold by caffeic and coumaric
acids. At high phenolic concentrations (� 1.6 mM),
ChAP1 is needed for maximum CCHD1 expression.
At micromolar levels of phenolics CCHD1 is as
strongly induced in chap1 mutants as in the wild
type. The pathogen thus detects phenolics by at
least two signalling pathways: one causing nuclear
retention of ChAP1, and another triggering induction
of CCHD1 expression. The low concentrations
required for induction of CCHD1 indicate fungal
receptors for plant phenolics. Symbiotic and
pathogenic bacteria are known to detect phenolics,
and our findings generalize this to a eukaryotic
pathogen. Phenolics and related compounds thus
provide a ubiquitous plant-derived signal.
 
Date 2010
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://ihbt.csircentral.net/284/1/556_2010_The_Fungal.pdf
Shanmugam, V and Ronen, M and Shalaby, S and Larkov, O and Rachamim, Y and Hader, R and Rose, M S and Carmeli, S and Horwitz, B A and Lev, S (2010) The fungal pathogen Cochliobolus heterostrophus responds to maize phenolics: novel small molecule signals in a plant-fungal interaction. Cellular Microbiology, 12. pp. 1421-1434.
 
Relation http://ihbt.csircentral.net/284/