Biochemical and Molecular Analyses of Gibberellin Biosynthesis in Fungi
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The plant hormone, gibberellin (GA), regulates plant growth and development. It was first isolated as a superelongation-promoting diterpenoid from the fungus, <I>Gibberella fujikuroi</I>. <I>G. fujikuroi</I> uses different GA biosynthetic intermediates from those in plants to produce GA<SUB>3</SUB>. Another class of GA-producing fungus, <I>Phaeosphaeria</I> sp. L487, synthesizes GA<SUB>1</SUB> by using the same intermediates as those in plants. A molecular analysis of GA biosynthesis in <I>Phaeosphaeria</I> sp. has revealed that diterpene cyclase and cytochrome P450 monooxygenases were involved in the plant-like biosynthesis of GA<SUB>1</SUB>. Fungal <I>ent</I>-kaurene synthase is a bifunctional cyclase. Subsequent oxidation steps are catalyzed by P450s, leading to biologically active GA<SUB>1</SUB>. GA biosynthesis in plants is divided into three steps involving soluble enzymes and membrane-bound cytochrome P450. The activation of plant GAs is catalyzed by soluble 2-oxoglutarate-dependent dioxygenases, which is in contrast to the catalysis of fungal GA biosynthesis. This difference suggests that the origin of fungal GA biosynthesis is evolutionally independent of that in plants.
- Agricultural and Biological Chemistry
Agricultural and Biological Chemistry 70(3), 583-590, 2006-03-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry