Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.15 (pectinase)
 2,440 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gene expression in fungi by ambient pH is regulated via a conserved signalling cascade whose terminal component is the zinc finger transcription factor PacC/Rim1p. We have identified a pacC orthologue in the vascular wilt pathogen Fusarium oxysporum that binds the consensus 5'-GCCAAG-3' sequence and is proteolytically processed in a similar way to PacC from Aspergillus nidulans. pacC transcript levels were elevated in F. oxysporum grown in alkaline conditions and almost undetectable at extreme acidic growth conditions. PacC+/- loss-of-function mutants displayed an acidity-mimicking phenotype resulting in poor growth at alkaline pH, increased acid protease activity and higher transcript levels of acid-expressed polygalacturonase genes. Reintroduction of a functional pacC copy into a pacC+/- mutant restored the wild-type phenotype. Conversely, F. oxysporum merodiploids carrying a dominant activating pacCc allele had increased pacC transcript and protein levels and displayed an alkalinity-mimicking phenotype with reduced acid phosphatase and increased alkaline protease activities. PacC+/- mutants were more virulent than the wild-type strain in root infection assays with tomato plants, whereas pacCc strains were significantly reduced in virulence. We propose that F. oxysporum PacC acts as a negative regulator of virulence to plants, possibly by preventing transcription of acid-expressed genes important for infection.
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PMID:The pH signalling transcription factor PacC controls virulence in the plant pathogen Fusarium oxysporum. 1269 20

SUMMARY The production of oxalic acid by Sclerotinia sclerotiorum is regulated by the ambient pH environment. This regulation and that of a few investigated pH-responsive genes is mediated in part by the zinc finger transcription factor encoded by pac1, an orthologue of the Aspergillus nidulans pacC gene. We manipulated the pac1 sequence by site-directed mutagenesis to create a dominant activating pac1(c) mutation and introduced this allele into a pac1 loss-of-function (Deltapac1) strain. Consistent with a constitutive activation of Pac1 function, oxalic acid accumulation in recovered Deltapac1-pac1(c) strains was largely independent of ambient pH. Likewise, all three Deltapac1-pac1(c) strains accumulated detectable pac1 transcripts in a pH 3 environment; however, accumulation of pac1 transcripts remained alkaline-inducible, but much reduced relative to wild-type in two of the three Deltapac1-pac1(c) strains. Surprisingly, the accumulation of pg1 and acp1 transcripts, normally favoured by low pH conditions, were up-regulated across the range of ambient pH conditions examined (pH 3.4-7.2). Accumulation of neutral pH-expressed endopolygalacturonase-6 (pg6) transcripts, however, did not differ from wild-type. In pathogenicity assays using Arabidopsis and detached tomato leaflets, Deltapac1-pac1(c) strains were reduced in virulence despite the ability to accumulate oxalic acid independent of the prevailing ambient pH environment. These results support the hypothesis that appropriate gene regulation in response to ambient pH is important for full S. sclerotiorum virulence independent of oxalic acid accumulation.
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PMID:An activating mutation of the Sclerotinia sclerotiorum pac1 gene increases oxalic acid production at low pH but decreases virulence. 2050 25