Construction of new gibberellin fermentation by a novel fungus phaeosphaeria sp. L487 and elucidation of its plant-like biosynthesis of gibberellin A_1

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1) Gibberellin production by the novel fungus Phaeosphaeria sp.L487.Gibberellin A_1 (GA_1) formation in its fermentations using shaken Sakaguchi flasks was stimulated in the 1.5% oatmeal medium as well as in the 0.4% Pharmamedia medium.Empolying optimized growing conditions (8% glucose, 1.5% oatmeal, 0.1% NH_4NO_3), concentrations of GA,of over 200 mug/ml were reached. Further, those of GA_1 of 300mug/ml were oberved by supplement of additional 3% glucose in the middle stage of GA_1 fermentation. New fungal GA,GA_<82> was isolated for the first time as crystalline from the culture. GA_4 and GA_9 were found at concentrations of 30 and 15 mug/ml, respectively, in the medium pH-controlled with K_2HPO_4 st 6.5-7.0.2) Elucidation of plant-like biosynthesis of gibberellin in Phaeosphaeria sp. L487.Minor GAs, GA_<12>, GA_<15> and GA_<20>, from this fungus were detected by GC-MS analysis.Using several labelled-GA precusors and a GA-biosynthetic inhibitor uniconazole, new fungal plant-like biosynthesis of GA_1 was revealed as the early-non-hydroxylation pathway from GA_<12>-aldehyde to GA_1 : GA_<12>-aldehyde*GA_<12>*GA_<15>*GA_<24>*GA_9*GA_4 (GA_<20>) *GA_1・In the GA_1-biosynthetic pathway, GA_9*GA_4 and GA_<20>*GA_1 were new fungal GA-metabolic routes. Ultracentrifuged pupernatant prepared from the mycelia catalized kaurene formation from labelled mavalonate, suggesting that kaurene synthase of the fungus is a soluble enzyme.