Showing papers on "Phytoalexin published in 1974"
TL;DR: The postulate that phytoalexin production is confined to cells undergoing necrobiosis remains in doubt because of the absence of techniques for the accurate localisation of the inhibitors within infected tissues.
Abstract: STUDIES on the role of phytoalexins in disease resistance in plants have been limited by the absence of techniques for the accurate localisation of the inhibitors within infected tissues. As a result the postulate of Muller and Borger1 that phytoalexin production is confined to cells undergoing necrobiosis remains in doubt2.
69 citations
TL;DR: It is concluded that the accumulation of the four antifungal compounds is important in restricting hyphal growth during both the hypersensitive reaction and during the formation of limited lesions.
Abstract: Inoculation of hypocotyls of Phaseolus vulgaris cv. Kievitsboon Koekoek with spores of an incompatible race of Colletotrichum lindemuthianum (race β) resulted in a hypersensitive response. Inoculation with a compatible race (race γ) caused lesions to form. In hypocotyls incubated at 17 °C, these lesions spread throughout the hypocotyl, whereas in hypocotyls incubated at 25 °C lesions became limited in size. Data are presented which demonstrate that four antifungal compounds, phaseollin, phaseollidin, phaseollinisoflavan and kievitone, accumulated in all these infected tissues. Experiments are also reported which describe the effects of phaseollin on mycelial growth of C. lindemuthianum and its ability to metabolize the phytoalexins. Results suggest that the apparent insensitivity of mycelial growth of C. lindemuthianum to phaseollin in vitro may be due to the conversion of phaseollin to non-toxic products. It is concluded that the accumulation of the four antifungal compounds is important in restricting hyphal growth during both the hypersensitive reaction and during the formation of limited lesions.
51 citations
TL;DR: The results suggest that phytoalexins such as capsidiol, even if not primary determinants of disease resistance, could influence the progress of disease and the sequence of subsequent colonization.
Abstract: Capsidiol, the phytoalexin from peppers, rishitin, the phytoalexin from potatoes, and 20 other derivatives or model compounds related to capsidiol were compared for fungitoxicity against a range of pathogenic and non-pathogenic fungi, using spore germination and growth assay procedures. Capsidiol was the most active compound tested (mean effective dose (ED50) vs. Phytophthora infestons, 1 × 10−5 M) and all derivatives examined had decreased activity. No correlations were found between sensitivity to capsidiol or rishitin and pathogenicity for peppers or potatoes, nor were there any clear correlations between structure and activity. Activity was greatly influenced by minor structural changes and such changes frequently had differential effects on different fungi. The results suggest that phytoalexins such as capsidiol, even if not primary determinants of disease resistance, could influence the progress of disease and the sequence of subsequent colonization.
38 citations
TL;DR: In this article, Phytoalexin Induction in Sweet Potato Roots by Amino Acids is described. But this method is not suitable for the extraction of sweet potato roots.
Abstract: (1974). Phytoalexin Induction in Sweet Potato Roots by Amino Acids. Agricultural and Biological Chemistry: Vol. 38, No. 12, pp. 2567-2568.
2 citations