1887

Abstract

The pea phytoalexin pisatin, at its inhibitory concentration, was shown to have two distinct inhibitory effects on amoebae of the cellular slime mould . One effect was cytolytic and was demonstrable even in non-growing cells whereas the second effect was observed only under conditions favourable to growth. Pretreatment with a sublethal concentration of pisatin induced the amoebae to acquire resistance to both these effects. Mutations in that alter membrane sterols and confer resistance to the polyene antibiotics nystatin and pimaricin blocked resistance to the growth-associated inhibitory effect but did not affect acquisition of resistance to the cytolytic effect. The double mutant HK412 displayed a partially constitutive resistance to the cytolytic effect but, like the mutants, was blocked in the acquisition of resistance to the growth-associated inhibitory effect. Pisatin-treated cells incubated in pisatin-free medium lost their ability to grow on pisatin-containing medium much more rapidly than they lost resistance to the cytolytic effect of pisatin. These results suggest that the induction of pisatin resistance may involve the turning-on of independent resistance mechanisms against the two inhibitory effects of pisatin. This could account for our inability to isolate pisatin-resistant mutants in a single step. The and mutants that have altered membrane sterols and are nystatin resistant displayed sensitivity to pisatin. The pisatin-sensitivity phenotype of the mutants was used in selections to identify complementing plasmids from an ordered genomic library. The association of pisatin sensitivity with membrane sterol alterations in both and supports the hypothesis that mechanisms underlying nondegradative pisatin resistance are evolutionarily conserved.

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/content/journal/micro/10.1099/00221287-139-12-3035
1993-12-01
2024-04-23
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References

  1. Bonner J.T. 1947; Evidence for the formation of cell aggregates by chemotaxis in the develoμMent of the slime mold Dictyostelium discoideum. Journal of Experimental Zoology 106:1–26
    [Google Scholar]
  2. Davis R.H., De Serres F.J. 1970; Genetic and microbiological techniques for Neurospora crassa. Methods in Enzymology 28A:79–143
    [Google Scholar]
  3. Denny T.P., VanEtten H.D. 1983; Characterization of an inducible, nondegradative tolerance of Nectria haematococca MP VI to phytoalexins. Journal of General Microbiology 129:2903–2913
    [Google Scholar]
  4. Denny T.P., Matthews P.S., VanEtten H.D. 1987; A possible mechanism of nondegradative tolerance of pisatin in Nectria haematococca MP VI. Physiological and Molecular Plant Pathology 30:93–107
    [Google Scholar]
  5. Ellis S.W., Rose M.E., Grindle M. 1991; Identification of a sterol mutant of Neurospora crassa deficient in Δ14,l5-reductase activity. Journal of General Microbiology 137:2627–2630
    [Google Scholar]
  6. Grindle M. 1973; Sterol mutants of Neurospora crassa: their isolation, growth characteristics and resistance to polyene antibiotics. Molecular and General Genetics 120:283–290
    [Google Scholar]
  7. Grindle M., Farrow R. 1978; Sterol content and enzyme defects of nystatin resistant mutants of Neurospora crassa. Molecular and General Genetics 165:305–308
    [Google Scholar]
  8. Kasbekar D.P., Bhavani Prasanna T. 1992; The nysB sunD double mutant of Dictyostelium discoideum is blocked in the acquisition of non-degradative resistance to the pea phytoalexin pisatin. FEMS Microbiology Letters 94:251–254
    [Google Scholar]
  9. Kasbekar D.P., Papavinasasundaram K.G. 1992; An inducible, nondegradative phytoalexin resistance mechanism in Dictyostelium discoideum is suppressed by mutations that alter membrane sterol composition. Applied and Environmental Microbiology 58:2071–2074
    [Google Scholar]
  10. Loomis W.F. 1987; Genetic tools for Dictyostelium discoideum. Methods in Cell Biology 28:31–65
    [Google Scholar]
  11. Raper K.B. 1935; Dictyostelium discoideum, a new species of slime mold from decaying forest leaves. Journal of Agricultural Research 50:135–147
    [Google Scholar]
  12. Scandella D., Rooney R., Katz E.R. 1980; Genetic, biochemical, and develoμMental studies of nystatin resistant mutants in Dictyostelium discoideum. Molecular and General Genetics 180:67–75
    [Google Scholar]
  13. Sellitrennikoff C.P., Sachs M.S. 1991; Lipofectin increases the efficiency of DNA-mediated transformation of Neurospora crassa. Fungal Genetics Newsletter 38:90–91
    [Google Scholar]
  14. Sussman M. 1966; Biochemical and genetic methods in the study of cellular slime mold develoμMent. Methods in Cell Physiology 22:397–410
    [Google Scholar]
  15. Sweigard J., VanEtten H.D. 1987; Reduction in pisatin sensitivity of Aphanomyces euteiches by polar lipid extracts. Phytopathology 77:771–775
    [Google Scholar]
  16. Vollmer S.J., Yanofsky C. 1986; Efficient cloning of genes of Neurospora crassa. Proceedings of the National Academy of Sciences of the United States of America 834869–4873
    [Google Scholar]
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