Kawaide Hiroshi
Division of Agriscience and Bioscience, Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology (TUAT), Tokyo, Japan.
Biosci Biotechnol Biochem. 2006 Mar;70(3):583-90. doi: 10.1271/bbb.70.583.
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.
植物激素赤霉素（GA）调控植物的生长和发育。它最初是作为一种促进超伸长的二萜类化合物从藤仓赤霉菌中分离出来的。藤仓赤霉菌利用与植物不同的赤霉素生物合成中间体来产生GA3。另一类产生赤霉素的真菌，稻瘟病菌L487，通过使用与植物相同的中间体来合成GA1。对稻瘟病菌中赤霉素生物合成的分子分析表明，二萜环化酶和细胞色素P450单加氧酶参与了GA1的类植物生物合成。真菌内贝壳杉烯合酶是一种双功能环化酶。随后的氧化步骤由细胞色素P450催化，产生具有生物活性的GA1。植物中的赤霉素生物合成分为三步，涉及可溶性酶和膜结合细胞色素P450。植物赤霉素的激活由可溶性2-酮戊二酸依赖性双加氧酶催化，这与真菌赤霉素生物合成的催化作用不同。这种差异表明，真菌赤霉素生物合成的起源在进化上独立于植物中的起源。
