gibberellin biosynthesis UPa:UPA00390 Biosynthesis of gibberellins (GAs), a large family of plant growth substances with distinct functions during the whole life cycle of higher plants. Gibberellins are involved in promotion of stem elongation, mobilization of food reserves in seeds and other processes. Gibberellin was first isolated as a superelongation-promoting diterpenoid from the fungus, Gibberella fujikuroi. G. fujikuroi uses different GA biosynthetic intermediates from those in plants. pathway GO:0009686 plant hormone biosynthesis