Molecular Mechanism of Gibberellin Signaling Repression by the DELLA Protein RGA in Arabidopsis

Duke University, Durham NC

Investigators

Abstract

IOS-0641548 (Tai-ping Sun) Title: Molecular Mechanism of Gibberellin Signaling Repression by the DELLA Protein RGA in Arabidopsis Abstract Gibberellin (GA) is an important plant growth hormone, which promotes seed germination, leaf expansion, stem elongation and flower development in higher plants. The dwarf cultivars of wheat and rice developed during the 'Green Revolution' in the 60s remarkably increased the grain yields. Recent studies revealed that these cultivars are modified in their GA production or responses to GA, illustrating the important role of this hormone in regulating plant development and in agriculture. GA-promoted growth and development is modulated by DELLA proteins, which are major negative regulators (repressors) of GA responses. GA, upon binding to its receptor, activates its response pathway by causing rapid degradation of DELLA. DELLA proteins are likely to function as transcriptional regulators and recent studies identified several key regulatory genes that are targets of DELLA in the model plant Arabidopsis. Two of these genes, one encodes transcription regulator (SCL3) and the other encodes an enzyme (RING) that may regulate stability of its downstream target protein(s). Genetic, molecular and biochemical approaches will be taken to investigate functions of SCL3 and RING in GA-regulated plant growth and development. DELLA proteins are functionally highly conserved in Arabidopsis and in many crop plants. For example, the semi-dwarf wheat cultivars, an essential component of the Green Revolution, contain mutations in the Rht loci that encode DELLA proteins. This study will likely to have a broader impact in improving quality of agricultural crops. In addition, a postdoctoral fellow and four undergraduate students will gain research experience in this project. The findings of this study will be incorporated into four undergraduate courses (including one lab course) at Duke University. Students will learn to appreciate how the information gained from studies in a model plant system can be used to improve agriculture practice and benefit society.