Analysis of RGA-Like 2 (RGL2), a gibberellic acid response regulator, in the flower development of Arabidopsis thaliana

Abstract

A GA regulator named RGL2 in Arabidopsis flower development was analyzed using molecular genetics approaches. It belongs to an important group of transcriptional regulators in GA signaling called DELLA proteins. The role of RGL2 in floral development is focused here, because previous studies showed RGL2 and RGA had effects on flower development. GUS staining and in situ hybridization techniques revealed RGL2 was expressed from stage 1 to 7 of flower development. RGL2 was also expressed in parts of the carpel, filaments and petals. Constitutive and conditional overexpression RGL2 did not produce major aberrations in floral tissues. However, overexpression of RGL2 in ga1-3 rga rgl2 caused floral defects, indicating RGL2 as a negative regulator of flower development. With an inducible expression system, we identified AP2, a floral homeotic gene, as a potential downstream target of RGL2. Other floral organ identity genes were not substantially affected. Protein tagging strategies employed revealed a serine/threonine protein kinase as a potential interacting co-effector of RGL2.