Biochemical and molecular analyses of gibberellin biosynthesis in fungi.
The plant hormone, gibberellin (GA), regulates plant growth and development. It was first isolated as a superelongation-promoting diterpenoid from the fungus, Gibberella fujikuroi. G. fujikuroi uses different GA biosynthetic intermediates from those in plants to produce GA3. Another class of GA-producing fungus, Phaeosphaeria sp. L487, synthesizes GA1 by using the same intermediates as those in plants. A molecular analysis of GA biosynthesis in Phaeosphaeria sp. has revealed that diterpene cyclase and cytochrome P450 monooxygenases were involved in the plant-like biosynthesis of GA1. Fungal ent-kaurene synthase is a bifunctional cyclase. Subsequent oxidation steps are catalyzed by P450s, leading to biologically active GA1. 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.
Kawaide
Hiroshi
H
Division of Agriscience and Bioscience, Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology (TUAT), Tokyo, Japan. hkawaide@cc.tuat.ac.jp
D002384:Catalysis; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005658:Fungi / Q000201:enzymology / Q000378:metabolism*; D005875:Gibberellins / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010944:Plants / Q000737:chemistry / Q000378:metabolism
D005875:Gibberellins; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases