Abstract
SULTR1;1 high affinity sulfate transporter is highly regulated in the epidermis and cortex of Arabidopsis roots responding to sulfur deficiency (-S). To identify the cis-acting element involved in the -S inducible expression, SULTR1;1 promoter was analyzed using transgenic Arabidopsis. Deletion and gain-of-function analysis using luciferase reporter gene revealed that the 16bp sulfur responsive element (SURE) from -2777 to -2761 of SULTR1;1 was sufficient and necessary for the -S response. The SURE contained an ARF binding sequence, but was not responsive to auxin, indicating its specific function in the -S response. The base substitution analysis indicated the significance of a 5bp sequence (GAGAC) within the ARF binding site as a core element. Microarray analysis of early -S response in roots indicated the presence of SURE core in the promoter regions of -S inducible genes, suggesting the existence of a common regulatory mechanism inducing -S response.
