PLANT-LIKE BIOSYNTHESIS OF GIBBERELLIN A(1) IN THE FUNGUS PHAEOSPHAERIA SP L487

Gibberellin A(12)(GA(12)), GA(15) and GA(20) were identified by full scan GC-MS from a culture filtrate of Phaeosphaeria sp. L487, in addition to the previously identified GAs, GA(1), GA(4), GA(9), GA(24), and GA(25).The early-non-hydroxylation pathway from GA(12)-7-aldehyde to GA(1) was shown to be present in the fungus by feeding studies of [1,2-H-3(2)]GA(4),[17-C-14]GA(9), [17-C-13,H-3]GA(12)-7-aldehyde and [17-C-13,H-3]GA(20). The fungus metabolized GA(9) to GA(1) via GA(4) and GA(20). Comparison of the conversion of GA(4) and GA(20) to GA(1) based on HPLC analysis indicated that the conversion of GA(4) to GA(1) was more effective than that of GA(20) to GA(1). The pathway from GA(9) to GA(1) via GA(4) and GA(20) is novel in microorganisms and like that of some higher plants.