While studying the cause of bakanae, Kurosawa found that a certain fungus created a surplus of this class of hormones, causing plants to become incapable of supporting their own weight and topple over.  
This class of hormones is synthesized from four isoprenoids in plastids, modified in the ER, and modified again in the cytosol. They act by degrading regulator DELLA proteins. This class of hormones stimulates the production of alpha amylase in aleurone cells, beginning the hydrolysis of starch from the endosperm in seeds. These hormones are commercially used to the increase in the size of grapes and grape bunches with the application of (*) GA3, the first of these hormones to be biosynthesized. While studying the cause of bakanae, Kurosawa found that a certain fungus created a surplus of this class of hormones, causing plants to become incapable of supporting their own weight and topple over.  For 10 points, name these plant hormones that promote dormancy breaking and stem elongation, discovered while searching for the cause of "foolish seedling" disease.
This class of hormones is synthesized from four isoprenoids in plastids, modified in the ER, and modified again in the cytosol.
{gibberellin}s