Molecular Plant Pathology (2003) 4, 177-186

Ian E. Wheeler, Derek W. Hollomon, Gary Gustafson, Jon C. Mitchell, Chris Longhurst, Ziguo Zhang and Sarah J. Gurr (2003)
Quinoxyfen perturbs signal transduction in barley powdery mildew (Blumeria graminis f.sp. hordei)
Molecular Plant Pathology 4 (3), 177-186
Abstract: Quinoxyfen is a protectant fungicide which controls powdery mildew diseases by interfering with germination and/or appressorium formation. Mutants of barley powdery mildew, Blumeria graminis f.sp. hordei, which are resistant to quinoxyfen produce fewer conidia, which germinate and form appressoria more promiscuously than do the prolific numbers of wild-type spores. This suggests that resistance bypasses host recognition signals. RT-PCR profiles of signal transduction genes, recorded during wild-type germling morphogenesis, reveals that quinoxyfen alters the accumulation of Protein Kinase C (pkc), pkc-like and catalytic subunit of Protein Kinase A (cpka) transcripts. Differential display-reverse transcription PCR identified a gene transcript in wild-type conidia that was absent, or much less abundant, in conidia from quinoxyfen-resistant mutants. This mRNA was not detectable 24 h after wild-type conidia were inoculated on to barley. It encodes a GTPase activating protein (GAP), which may interact with a small molecular weight Ras-type GTP binding protein. In the presence of quinoxyfen, the gap mRNA remains throughout germling morphogenesis. The involvement of GAP in resistance suggests that quinoxyfen inhibits mildew infection by disrupting early cell signalling events.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Sarah J. Gurr, Derek W. Hollomon

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Blumeria graminis