O. S. Otroshchenko

Metabolites of the pathogenic fungus Verticillium dahliae VI. Pentaketide metabolites and neutral lipids of virulent and avirulent strains

SummaryA comparative study of the amounts of the phytotoxic pigment PKZh-1 and of extracellular and intracellular lipids in five strains and mutants ofVerticillium dahliae differing in virulence and in the nonpathogenic fungusV. lateritium has been made. A definite correlation has been found between virulence and PKZh-1 content.It has been established that the extracellular lipids are produced in considerable amounts by the virulent strains while in the avirulent mutants and inV. lateritium they are absent or present in only very small amount. The contents of neutral lipids in the mycelia of strains and mutants differing in virulence do not differ significantly. There are definite differences in the compositions of the neutral lipids and in the fatty-acid compositions of the individual classes of lipids.From the culture liquid of one of the avirulent strains (R-196), 3,6,8-trihydroxy-1,2,3,4-tetrahydronaphthalen-1-one has been isolated.

Metabolites of the pathogenic fungusVerticillium dahliae. IX. Pentaketides of mutants and their role in the biosynthesis of melanin

From mutants of the fungusVerticillium dahliae Kleb. having different genetic blocks in the biosynthesis of melanin we have isolated and identified scytalone, flaviolin, 4-hydroxyscytalone, and 2-hydroxyjuglone and have detected 3,4,8-trihydroxytetralone and 4,8-dihydroxytetralone, which, in combination with the results of complementation analysis, have confirmed the scheme of melaninogenesis inV. dahliae put forward previously. The participation of 1,3,6,8-tetrahydroxynaphthalene in the basic pathway of the biosynthesis of melanin has been shown.

Lipids and secondary metabolites of Fungi Imperfecti causing plant diseases

The review generalizes information on the composition of the lipids and the structure of the secondary metabolites of phytopathogenic Fungi Imperfecti. The chemical properties of the main classes of lipids, their biosynthesis, their interconversions, and their possible role in the mutual relationships with the plant host are discussed. Methods for the diagnosis and practical ways of finding chemical agents for the fight against infectious diseases of plants are substantiated theoretically.

Metabolites of the pathogenic fungus Verticillium dahliae . XI. Primary structure of the polypeptide moiety of the phytotoxic pigment PKZh-1

The sequence of the 27 amino acid residues composing the polypeptide moiety of the phytotoxic metabolite PKZh-1 of the fungusV. dahliae has been determined on the basis of the structures of tryptic and chymotryptic peptides. It has been established that the linkage of the polypeptide with 2,5,7-trihydroxy-1,4-naphthoquinone (flaviolin), which is the chromophoric moiety of PKZh-1, is effected through an ester bond formed by the carboxy group of the C-terminal amino acid and one of the hydroxy groups of flaviolin.

Metabolites of the pathogenic fungusVerticillium dahliae. IV. Influence of the source of carbon on the lipid composition of the fungusVerticillium dahliae

SummaryThe compositions of the neutral lipids and the fatty-acid compositions ofVerticillium dahliae Kleb. grown in a fermenter with various sources of carbon-containing nutriment have been studied. It has been shown that the capacity of the fungus for synthesizing lipids and the quantitative and qualitative compositions of the neutral lipids and the fatty acids change according to the source of carbon-containing nutriment. Under the conditions of growth of the fungus in a fermenter, in some cases the formation of linolenic acid and of saturated iso acids is observed.It has been established that whenV. dahliae is grown on sucrose, the neutral lipids of the fungus include a chlorine-containing compound. The chlorine in the initial oil has been determined quantitatively.

Metabolites of the pathogenic fungusVerticillium dahliae III. The lipid composition ofVerticillium dahliae

SummaryThe compositions of the neutral lipids of the mycelium and of the culture liquid from the pathogenic fungusVerticillium dahliae Kleb. have been investigated for the first time. The fatty-acid compositions of the main lipid fractions and the glyceride composition of the triglyceride fraction have been determined. The main acids of all the fractions are the 16:0 and 18:1 acids and in the triglyceride fraction, additionally, the 18:2 acid. Diisobutyl phthalate has been found in the combined neutral lipids of the fungal mycelium.

Metabolites of the pathogenic fungus Verticillium dahliae . I. 1 H and 13 C NMR spectra of the extracellular lipids

SummaryFrom the culture liquid of the fungusV. dahliae an extract has been isolated which contains paramagnetic centers and causes the symptoms of verticillium wilt of the cotton plant. By chromatography and1H and13C nuclear magnetic resonance it has been shown that this extract includes triglycerides and fatty-acid residues of the oleic series with various degrees of unsaturation.

Metabolites of the pathogenic fungus Verticillium dahliae II. Components of the fraction of neutral lipids from the culture liquid

SummaryDi-2-ethylhexyl phthalate has been isolated from the neutral lipids fraction of the culture liquid of the fungusVerticillium dahliae Kleb. Its1H and13C magnetic resonance spectra have been obtained, and an assignment of the signals has been made.On the basis of their UV, IR, and ESR spectra, the chromogenic components of the neutral lipid fractions have been assigned to the melanins.