ISOLATION AND CLONING OF OsGSL8 GENE AND ITS OVEREXPRESSION IN ARABIDOPSIS THALIANA

Abstract

Rice is the most widely consumed cereal grain in the world. It is responsible for one-fifth of the caloric intake of humans worldwide. Hormones play an important role in plant growth and development. Gibberellic acid (GA) is an important plant hormone which regulates various aspects of plant biology, such as stem elongation, seed germination, plant stature, leaf expansion, and control of apical dominance. The GAST (Gibberellic Acid Stimulated Transcript) gene family is a family of genes whose expression is induced by various cellular processes regulated by GA. Genes of GAST family regulate plant developmental processes such as cell elongation, cell division, seed germination, root and flower development and also involved in biotic and abiotic stress response. In rice, initially, three genes OsGSR1, OsGASR1, and OsGASR2 were identified. However, currently 9 genes have been defined as part of the GAST gene family in rice. All genes of this family encode proteins of 80-152 amino acids, each characterized by a conserved C-terminal domain of 59-64 amino acids. Within this domain, a residue of 12 cysteine residues is perfectly conserved. Some members of the rice-GAST-like family have not yet been characterized. In this study, characterization of a member of the GAST-like gene family, OsGSL8 has been attempted. An overexpression construct of this gene was prepared and cloned into pCAMBIA1301 binary vector, which was transformed into Arabidopsis thaliana plant via Agrobacterium, to create an overexpression line of OsGSL8 in Arabidopsis. In future, overexpression line of OsGSL8 could be used for the functional characterization of this gene. A reporter line of proOsGSL8 was also prepared, for observing tissue-specific expression. The T1 plants of reporter line showed strong GUS expression in leaves. Further phenotypic analysis of these transgenic line and analysis of its homolog mutant in Arabidopsis is necessary to uncover its conserved or distinct role in plant development and stress response.