Abstract
Storage proteins in cotyledon of legume plants are degraded by proteases expressed during seed germination and are mobilized to the embryonic axis for its growth. In aleuron layers of rice or barley, expression of proteases is induced by gibberellin (GA). We examined whether GA regulate expression of a protease, EP-C1 in germinated cotyledons of common bean. Expression of EP-C1 was repressed by GA biosynthesis inhibitors, suggesting that GA regulates expression of EP-C1 in germinated cotyledons. Because a DELLA protein, RGL2 is known to be involved in GA-regulated germination of Arabidopsis seeds, we examined whether RGL2 regulated EP-C1 expression. The promoter activity of EP-C1 was repressed by over-expression of RGL2, suggesting that DELLA proteins regulate EP-C1 expression in germinated cotyledons.
