Gibberella fujikuroi gibberellins from

Gibberellins.—The 13C n.m.r. spectra of the gibberellins have been assigned.6 7 The results have been used8 in the elucidation of the structure of gibberellin A40 (84) which was isolated from Gibberella fujikuroi. Gibberellin A43 (85) has been... 

U. Bearder, J.R., MacMillan, J., Phinney, B.O. "Fungal products. Part XIV. Metabolic pathways from ent-kaurenoic acid to the fungal gibberellins in mutant Bl-J+la of Gibberella fujikuroi." J. . . Perkin Trans. 1975, 1, 721-726. 

Harrison, D.M., MacMillan, J. "Two new gibberellins, Ag4 and A25 from Gibberella fujikuroi their isolation, structure, and correlations with gibberellin A13 and Ane." J. Chem. 

Riboflavin is produced by Clostridium, Ascomycetes and Candida species. The yield can be as high as 5 g 1 1 after 7 days 60). Gibberella fujikuroi is utilized for the synthesis of gibberellins, a group of plant hormones used for plant growth promotion. Glucose, molasses, lipid (corn oil) are usually used as carbon sources. Vitamin B12 may also be synthesized from alcohols and hydrocarbons. 

The fungus Gibberella fujikuroi produces the gibberellins and the pigment bikhaverin. Some strains also produce the fusarins, e.g. 4.101, and fumanosins, e.g. 4.102, which are serious mycotoxins and phytotoxins. Cyclopentane fatty acids of the jasmonic acid type such as V-jasmonyl isoleucine (4.103) and its dihydro derivative have also been isolated from Gibberella fujikuroi. 

Some microbiological reactions were attempted either on natural kaurane diterpenoids isolated from Sideritis or on their hemisynthetic derivatives, by incubating them with Gibberella fujikuroi. The purpose was the transformation of the products into gibberelline derivatives. However, epicandicandiol (7) yielded no gibbane compounds, only oxidation of the 19-Me occurred, with the formation of the CH2OH and COOH derivatives (A) and (B) [112]. 

Figure 6.55. Gibberellin 20-oxidase from the fungus Gibberella fujikuroi is a multifunctional P450 that catalyzes the angular demethylation of GAjj to produce the lactone GA,.

A simple method of screening for presumptive mutants of Gibberella fujikuroi is described. The use of one mutant (Bl-41a) in the elucidation of the gibberellin biosynthetic pathway from ent-kaurenoic acid and in the metabolism of substrate analogues is briefly reviewed. Some preliminary results are described on the investigation of the inhibition of individual biosynthetic steps by nitrogen in the medium. 

A number of aspects of kaurene and gibberellin biosynthesis have been discussed during the year. The incorporation of [3 - H3]mevalonic acid into ( —)-kaurene (42) by a cell-free system from Gibberella fujikuroi has been studied. The labelling pattern excludes a ( —)-pimaradiene (43) from the biosynthesis. The previously reported low, but specific, incorporation of... 

Cross, B. E., and I. L. Gatfield New Metabolites of Gibberella fujikuroi. Part XVII. The Partial Synthesis of Gibberellin Ais Norketone from 7-Hydroxykaurenolide. J. Chem. Soc. (C) 1971,1539. 

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