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1.
The metabolism of [14C]triadimefon, triadimenol, diclobutrazol, and the oxo-analogue of diclobutrazol by the basidiomycete fungi Coriolus versicolor and Rhizoctonia solani was studied. Reduction of >C = 0 to >CHOH (activation) was more important for triadimefon than oxo-diclobutrazol. Conversely, oxidation of >CHOH to >C = 0 (deactivation) occurred to a greater extent with diclobutrazol than triadimenol. Formation of primary alcohol metabolites, a possible detoxication route, occurred more with diclobutrazol and its oxo-analogue than with triadimefon and triadimenol. The implications of the reduction/oxidation processes and primary alcohol formation on fungitoxicity of the applied triazolymethane are discussed. The enantiomeric composition of metabolically produced triadimenol is discussed in relation to the in vitro activity of triadimefon supplied against each fungus. 相似文献
2.
Maya Gasztonyi 《Pest management science》1981,12(4):433-438
The ratio of the two diastereomeric forms of triadimenol, produced by the reduction of triadimefon in various fungi, was studied. The reduction of triadimefon in fungi seems to be a concentration-dependent process, the virtual irreversibility of which is proved. Not only the degree of triadimefon reduction, but also the ratio of the triadimenol diastereomers produced, was characteristic for each of the fungal species. A direct correlation, between the production of the more active diastereomeric form and the sensitivity of the fungal species to triadimefon, was observed. 相似文献
3.
The uptake and metabolism of triadimefon by mycelia of fungi, sensitive or resistant to triadimefon, were studied. In the mycelia the triadimefon content accumulated to 20-40-fold of the external concentration, irrespective of the sensitivity of the fungus. In the course of the metabolism a highly fungitoxic product, triadimenol, was formed. In mycelia of sensitive fungi this transformation was at a high rate whereas it could not be demonstrated or only to a low extent in resistant types. The material produced by the sensitive fungi was effective also against fungi basically resistant to triadimefon. Based on these observations, triadimefon has to be regarded as the precursor of triadimenol. In the species investigated, selectivity may be related mainly to the rate of activation. In higher plants the metabolism of triadimefon showed a similar pattern, but was slower than with fungi. As the transformation into triadimenol (activation) begins thus early in the host tissues, the systemic fungitoxic effect is also influenced by the host plant itself. Regarding the speed of activation differences were found between the four plant species investigated. 相似文献
4.
Metabolism of the triazolylmethane fungicides triadimefon, triadimenol, and diclobutrazol by Aspergillus niger was studied using a replacement culture technique and 14C substrates. Components of metabolite mixtures were characterized by TLC, GLC, radio-GC, and GC-MS analyses of the free materials and their trifluoroacetate and trimethylsilyl ether derivatives. The three compounds underwent a common metabolic change involving oxidation of C(CH3)3 to C(CH3)2CH2OH. In this work the isopropyl analog of triadimefon, previously reported as a metabolite, was an artifact and resulted from nonbiological oxidation of the corresponding primary alcohol. The fungus also reduced triadimefon to triadimenol, giving a mixture of 1R2S, 1S2R and 1R2R, 1S2S diastereoisomers. The less fungitoxic 1R2S, 1S2R triadimenol predominated, so that this conversion may be directly associated with the relative insensitivity of A. niger to triadimefon. Implications of oxidative and reductive metabolism of these fungicides are suggested with particular reference to the differing fungitoxicities of diastereoisomers and enantiomers. 相似文献
5.
Botrytis cinerea, grown in shake culture in a liquid nutrient medium containing different amounts of triadimefon (4–40 mg litre?1), produced triadimenol as the sole major metabolite. Analysis by gas-liquid chromatography (g.l.c.) showed the presence of (1R,2S) and (1S,2S)-triadimenol, but no (1S,2R) or (1R,2R)-enantiomer. The proportion of (1R,2S) to (1S,2S)-triadimenol decreased over the period 6 to 168 h and with increased amounts of applied triadimefon. The implications of these patterns of metabolism are discussed in terms of overall fungitoxicity, the stereospecificity of the reduction process and the shortcomings of conventional, non-chiral analysis of diastereoisomers by g.l.c. for assessing the sensitivity of fungi to such fungicides as triadimefon. 相似文献
6.
Benodanil, triadimefon or triadimenol, prepared as solutions (30 g litre?1) in a mixture of N-methyl-2-pyrrolidone and xylene(1+ 9 by volume), or benodanil, prepared by diluting an emulsified concentrate with water, were applied to the surface of stumps produced by removing branches from apple trees. The active ingredients penetrated in fungitoxic amounts at least 6 cm below the wound surface, except when diluted benodanil e. c. was used. No such penetration occurred when the stumps were treated with acrylic paints containing the same ingredients. Triadimefon and triadimenol persisted within the wood for at least 273 days. No treatment inhibited callus formation but none appeared to enhance it. There were more saprophytic fungi in samples taken from treated than from untreated stumps, and the number of microorganisms present in the wood decreased with distance from the wound surface. Only one basidiomycete fungus was present in wood samples taken 273 days after treatments were carried out. 相似文献
7.
Isolates of Erysiphe graminis f. sp. hordei and tritici with decreased sensitivity to triadimefon showed cross-resistance to other inhibitors of sterol C-14-demethylation, such as triadimenol, propiconazol, diclobutrazol, prochloraz and nuarimol. The isolates exhibited a moderate degree of resistance to these compounds. No cross-resistance was detected to tridemorph, fenpropimorph and pyrazophos. The resistant hordei isolates were more sensitive to ethirimol than the sensitive isolate. The competitive abilities of resistant hordei and tritici isolates were inferior to that of the sensitive isolates. In the presence of the fungicides no differences in germination, appressorium formation and penetration between the sensitive and resistant isolates were observed; 48 h after inoculation the sensitive isolate showed several morphological alterations and further fungal development was arrested. At four to five times higher doses of triadimefon, similar morphological alterations were detected in the resistant isolate. Low concentrations of triazole fungicides which slightly affected mycelium growth of both the sensitive and the resistant isolate of f.sp. hordei severely inhibited development of conidiophores of the sensitive isolate whereas that of the resistant isolate was hardly affected. 相似文献
8.
三唑酮是一种重要的橡胶树白粉病防治药剂,明确三唑酮及其代谢物三唑醇在橡胶树上的迁移富集行为有利于提高其农药的靶标利用率。本研究基于QuEChERS法,采用气相色谱-串联质谱(GC-MS/MS)技术首次建立了三唑酮和三唑醇在橡胶树植株根、茎、叶中的残留分析方法。采用水培条件下根部施药和土培条件下叶部施药的方式,分别研究了三唑酮及三唑醇在橡胶树植株中的迁移富集行为。结果表明：橡胶树植株可快速将三唑酮代谢成三唑醇,2种药剂均可从植株根部通过茎部迁移至叶部,但在植株各部位中的富集行为具有较大差异,其生物富集系数大小依次为根部>茎部>叶部,且茎部和叶部的转运系数均小于1,表明三唑酮及三唑醇很难在橡胶树植株中向上迁移,易被根部富集;在对橡胶树植株叶部施药时,三唑酮亦可快速代谢成三唑醇,2种农药在植株不同部位的叶片间迁移能力较差。该研究可为优化三唑酮等农药在橡胶树上的施用方案提供重要的数据支撑。 相似文献
9.
The metabolism of triforine, chloraniformethan, the α-(pyrimidin-5-yl)benzhydryl alcohols (fenarimol, nuarimol and triarimol), the trityl-azoles (fluotrimazole and clotrimazole), and the morpholine types of sterol inhibitors is reviewed; the metabolism of the azolyl-alkane derivatives (mainly triadimefon and triadimenol) is discussed in detail. Redox and hydrolytic reactions are of primary importance. Enzymic inactivation may be one factor influencing fungicide selectivity. Metabolism is the dominant factor of selectivity if it represents the activation process, as with triadimefon. Transformations in higher plants do not differ significantly from those occurring in fungi, except that factors such as the formation of conjugates with natural compounds of plant tissues also play a role, as with triforine and triadimenol. The selectivity of fungitoxic action may be influenced by metabolism both in the host plant and the pathogen. 相似文献
10.
三唑酮、三唑醇对小麦纹枯病菌形态和生理的影响 总被引：19，自引：0，他引：19
小麦纹枯病菌(Rhizoctonia cerealis)在加入三唑酮(Triadimefon)或三唑醇(Triadimenol)的培养液中生长时,菌丝形态和生理发生明显的改变。菌丝畸形,表现为细胞肿大,细胞分隔处菌丝缢缩;药剂处理后,等量菌丝的麦角甾醇含量下降,1、5μg/ml的三唑酮和三唑醇处理,麦角甾醇含量比对照减少45.155.9%和27.5、48.9%;菌丝在药剂处理后,电解质渗漏增加,5μg/ml药剂处理一小时后,三唑酮组的菌丝之细胞电解质渗漏达2.58%,三唑醇组的渗漏为2.19%,空白对照组仅为0.65%。本研究结果表明,三唑酮、三唑醇对小麦纹枯病菌具有直接的伤害作用。 相似文献
11.
Strains of Pseudocercosporella herpotrichoides collected in France on winter wheat give either fast-growing mycelial colonies with regular margins or slow-growing mycelial colonies with irregular margins. Most of the fastgrowing isolates were sensitive to triadimenol (EC50 below 2mg litre?1), but some of them were resistant to this inhibitor of sterol C-14 demethylation. In contrast, all the slow-growing strains were highly resistant to triadimenol (EC50 greater than 100 mg litre?1). This resistance was also expressed in inhibition of germ-tube elongation. Positive cross-resistance was observed between most of the inhibitors of sterol C-14 demethylation, with the exception of some imidazole derivatives (clotrimazole, prochloraz). All the fast-growing strains were tolerant to fenpropimorph and fenpropidin whereas the slow-growing ones were susceptible; the reverse was true with piperalin and tridemorph. All the field isolates were inhibited to the same extent by the inhibitors of squalene-epoxidase, nafifine and terbinafine. Two types of mutant resistant to triadimenol have been induced under laboratory conditions from sensitive fast-growing strains. The most common mutants were resistant to all the inhibitors of sterol C–14 demethylation and also in some conditions to fenpropimorph, tridemorph and the inhibitors of squalene-epoxidase. The other mutants were characterised by a reduced spectrum of cross-resistance between triadimenol and the other inhibitors of sterol biosynthesis. The field isolates and laboratory mutants resistant to triadimenol and propiconazole were also resistant to each of the four enantiomers of these two fungicides. 相似文献
12.
The fungicides triadimefon and triadimenol markedly reduced growth of coleoptiles, primary leaves, and roots of barley seedlings when grown for 7 days in petri dishes in the dark. The addition of gibberellins (A1, A3, A4, A7, A9) alleviated growth retardation of primary leaves and coleoptiles induced by the fungicides. While fungicide-induced growth retardation of the shoots was partly relieved by kinetin, IAA did not show an alleviating activity. Triadimefon and triadimenol also substantially retarded the elongation of shoots of tomato and cotton plants and simultaneous application of GA3 nullified the retardation. The fungicides only slightly interfered with both α-amylase production of intact germinating barley seed and the GA3-induced α-amylase synthesis in barley endosperm. On the other hand, extracts of triadimefon- and triadimenol-treated shoot tissue of 10- to 12-day-old barley plants contained substantially lower gibberellin-like activity than control shoots. Both compounds also interfered in sterol metabolism of shoots of barley seedlings when compared to control plants, treatment resulted in lower amounts and altered proportions of C-4,4-desmethyl sterols. While both fungicides inhibited synthesis of C-4,4-desmethyl sterol fraction, sterols possessing C-4 and C-14-methyl groups were accumulated. It is assumed that triadimefon and triadimenol interfere in gibberellin and sterol biosynthesis in barley seedlings by inhibiting oxidative demethylation reactions. 相似文献
13.
Geoffrey A. Carter Sheila J. Kendall Raymond S. Burden Carolyn S. James Terence Clark 《Pest management science》1989,26(2):181-192
Isolate 840905 of Cladosporium cucumerinum, when grown on agar or in liqiud medium, was sensitive to triadimenol, HWG 1608 (tebuconazole), fenpropimorph and pimaricin but relatively resistant to terbinafine. Conversely, isolate 49628 was sensitive to terbinafine but relatively resistant to the other fungicides. Changes in sterol composition following treatment with the fungicides reflected the known modes of action of each fungicide. When individual enantiomers of triadimenol were tested against isolate 840905 the order of activity in reducing mycelial growth was 1 S, 2R > 1R, 2R > 1R, 2S ≈? 1S, 2S, and this was paralleled by the depletion of ergosterol and the appearance of 14α-methyl sterols. Isolate 49628 had a greater saturated:unsaturated fatty acid ratio than did isolate 840905 but no major changes in fatty acid composition of either isolate were induced by fungicide treatment. There appears to be no obvious explanation for the differences in fungicide sensitivity of the isolates in terms of their lipid compositions. 相似文献
14.
A laboratory assay to determine the sensitivity of Rhynchosporium secalis to the fungicide triadimenol 总被引：2，自引：2，他引：0
D. W. HOLLOMON 《Plant pathology》1984,33(1):65-70
Thirty single-spore isolates of Rhynchosporium secalis were assayed in vitro to assess relative sensitivities to the fungicide triadimenol. Minimum inhibitory concentrations ranged from 0.2 to 3.2 μg/ml. Isolates collected in 1981 from winter barley crops treated with triadimenol + tuberidazole, triadimefon, or prochloraz were as sensitive as those from untreated crops, and four isolates collected prior to the widespread use of these fungicides were not especially sensitive. All isolates tested in the greenhouse on winter and spring barley were controlled by Baytan (triadimenol and fuberidazole). 相似文献
15.
The effects of the sterol biosynthesis inhibitor (SBI) fungicides fenarimol, fenpropimorph, imazalil, prochloraz, propiconazole and triadimenol on growth and sterol composition of Ustilago maydis, Botrytis cinerea and Pyrenophora teres, grown from spores or sporidia in liquid culture, were determined. Growth of U. maydis was only slightly inhibited by SBI fungicides at concentrations which caused considerable changes in both sterol content and composition. Conversely, in B. cinerea and P. teres, growth was strongly inhibited under conditions where ergosterol was still the predominant sterol, suggesting that, in these two fungi, growth may be more sensitive to SBI fungicides than overall sterol production. Demethylase inhibitor fungicides behaved as a homogeneous group in their effects on growth and on sterol profiles of the three fungi studied. 相似文献
16.
When introduced as a seed treatment 5 years ago, triadimenol (Baytan) was more effective against Erysiphe graminis f. sp. hordei than was the alternative ethirimol (Milstem). This contrasts with the current situation on the powdery mildew-susceptible cv. Golden Promise, where ethirimol is generally better than triadimenol. In part this reflects a decline in the performance of triadimenol seed treatment, as a result perhaps of some decrease in sensitivity to this fungicide. However, laboratory assays of field isolates also revealed that negatively correlated cross-resistance between triadimenol and ethirimol might exist. In field trials the sensitivity of E. graminis to triadimenol was indeed increased after treatment with ethirimol, but triadimenol hardly altered sensitivity to ethirimol. The possible causes of these changes in fungicide sensitivity are discussed. 相似文献
17.
18.
A. E. Kalamarakis V. P. Demopoulos B. N. Ziogas S. G. Georgopoulos 《European journal of plant pathology / European Foundation for Plant Pathology》1989,95(Z1):109-120
Mutants ofNectria haematococca var.cucurbitae with high resistance to triadimenol could be isolated at high frequency. Resistance of 30 such mutants studied, was due to a mutation at thetri-1 locus, that maps in linkage group I, 10 cross-over units from the mating type locus. Thetri-1 mutation has no obvious effects on growth and sporulation on media without fungicide and on virulence for squash seedlings and mature fruit. In addition, a resistant mutant killed all of artificially inoculated seedlings in the presence of triadimenol at a concentration which gave 100% protection against the original wild type strain. Thetri-1 mutants were crossresistant at various levels to triadimefon, bitertanol, and propiconazol, but not to non-triazole SBIs. Their sensitivity to three imidazole derivatives was even higher than that of the wild type strains. This is believed to be the first report of a major gene for resistance to an SBI fungicide.Isolatie vanNectria haematococca var.cucurbitae mutanten met een hoog niveau van resistentie tegen triadimenol bleek zeer gemakkelijk. Uit genetische analyse van 30 van deze mutanten bleek dat in alle een mutatie voorkwam in de tri-1 locus die kon worden gelokaliseerd op koppelingsgroep I, 10 overkruisingseenheden verwijderd van de mating-type locus. Detri-1 mutatie had geen waarneembare effecten op groei en sporulering van de schimmel op fungicide-vrij medium en op pathogeniteit ten aanzien van zaailingen en rijpe vruchten van pompoen.Triadimenol-behandeling van zaailingen bleek aantasting door de resistente mutant niet te kunnen voorkomen, terwijl behandeling wel effectief bleek tegen de ouderstam. 相似文献
19.
Shantagouda G. Patil Peter H. Nicholls Keith Chamberlain Geoffrey G. Briggs Richard H. Bromilow 《Pest management science》1988,22(4):333-342
The degradation rates in soil of 1-benzyltriazole together with six analogues having substituents in the phenyl ring and two commercial triazole fungicides, PP450 and triadimefon, were determined at 15°C and 20 % soil water content. The order of degradation rates of the benzyltriazoles was H > 4-OCH3 > 4-F>4-Cl.4-≥tert-C4Hg3,4-diCl>3-CF3. Thus, in general, persistence was enhanced by electron-withdrawing substituents and by lipophilic groups that increased sorption by soil. Of the commercial fungicides, PP450 was degraded very slowly (half-life 578 days) while triadimefon was quickly converted (half-life 15 days) to the corresponding alcohol, triadimenol, which in turn was degraded very slowly. The effects of temperature and soil water content on rate of degradation were studied for 1-benzyltriazole and 1-(4-fluorobenzyl)triazole. The rate of degradation of 1-benzyltriazole was more sensitive to soil temperature and water content than was that of 1 -(4-fluorobenzyl)triazole. The influence of these results on the input data required by models which simulate persistence in field soil is discussed. 相似文献
20.
ABSTRACT Single-conidial isolates of Uncinula necator from (i) a population representing two vineyards with no previous exposure to sterol demethylation inhibitor (DMI) fungicides ("unexposed," n = 77) and (ii) a population representing two vineyards in which powdery mildew was poorly controlled by triadimefon after prolonged DMI use ("selected," n = 82) were assayed to determine distributions of sensitivities to the DMI fungicides triadimenol (the active form of triadimefon), myclobutanil, and fenarimol. Median 50% effective dose (ED(50)) values (micrograms per milliliter) in the selected versus unexposed populations were 0.06 versus 1.9 for triadimenol, 0.03 versus 0.23 for myclobutanil, and 0.03 versus 0.07 for fenarimol, respectively. Isolates were grouped into sensitivity classes according to their ED(50) values, and those from the selected population were categorized as resistant if the frequency of their sensitivity class had increased significantly relative to levels found in the unexposed population (ED(50) values exceeding 0.56, 0.18, and 0.18 mug/ml for triadimenol, myclobutanil, and fenarimol, respectively). Of the 76 isolates defined as resistant to triadimenol, 64% were classified as cross-resistant to myclobutanil, 18% were classified as cross-resistant to fenarimol, and 17% were classified as resistant to all three fungicides; 25% of the isolates classified as resistant to myclobutanil also were classified as resistant to fenarimol. Similar cross-resistance relationships were revealed when all isolates were examined by regressing log ED(50) values for each fungicide against those for the remaining two fungicides to determine the correlation coefficients (e.g., r = 0.85 for triadimenol versus myclobutanil and 0.56 for triadimenol versus fenarimol). The restricted levels of cross-resistance indicated by these data, particularly between fenarimol and the other two fungicides, is in sharp contrast to the high levels of cross-resistance among DMIs reported for some other pathogens and has significant implications with respect to programs for managing grapevine powdery mildew and DMI resistance. 相似文献