Molecular characterization of OsCURT1A from upland rice in response to osmotic stress

Abstract

CURT1 proteins in Arabidopsis thaliana have been reported to be important for inducing grana curvature. Currently, we have identified transcript encoding CURT1A from Oryza sativa cv. indica through RNA-seq analysis and characterised using heterologous system in Arabidopsis. The OsCURT1A gene shares 80% of its amino acid sequence with Arabidopsis AtCURT1A. Phylogenetic analysis revealed that the OsCURT1A is also closely related to the CURT1 proteins in other choloroplast- conatining organisms. In silico analysis of OsCURT1A promoter shows that several cis-elements related to stress are present in the 5' upstream from the coding region. Under normal conditions, there were no notable changes in the phenotype and chlorophyll a;b ratio between three Arabidopsis genotypes, which were overexpressed (35S::OsCURT1A), T-DNA insertional mutant line (atcurt1a), and Wild type (Col-0). However, overexpression of OsCURT1A under salinity condition demonstrate high chlorophyll a:b compared to Col-0, whereas, the lack of atcurt1a gene in the mutant line showed reduced chlorophyll a:b ratio. These results indicate that the OsCURT1A might have a function as salt-stress related gene, which may indirectly regulate the chlorophyll a:b ratio. Therefore, OsCURT1A can be used as a potential candidate for salinity stress tolerance in crop improvement.