Comprehensive analysis of regulatory elements of the promoters of rice sulfate transporter gene family and functional characterization of OsSul1;1 promoter under different metal stress

Adverse environmental conditions including heavy metal stress impose severe effects on the plant growth and development limiting productivity and yield. Studies demonstrated that changes in genome-wide expression modulate various biochemical processes and molecular components in response to heavy metal stress in plants. Some of the key components involved in such a regulation are the transcription initiation machinery, nucleotide sequence of promoters and presence of cis-acting elements. Therefore, identification of the putative cis-acting DNA sequences involved in gene regulation and functional characterization of promoters are important steps in understanding response of plants to heavy metal stress. In this study, comprehensive analysis of the proximal promoters of members of rice sulfate transporter gene family which is an essential component of stress response has been carried out. Analysis suggests presence of various common stress related cis-acting elements in the promoters of members of this gene family. In addition, transcriptional regulation of the arsenic-responsive high affinity sulfate transporter, OsSul1;1, has been studied through development of Arabidopsis transgenic lines expressing reporter gene encoding -glucuronidase under the control of OsSul1;1 promoter. Analysis of the transgenic lines suggests differential response of the OsSul1;1 promoter to various heavy metals as well as other abiotic stresses.