Abstract
Sulfur (S) is an essential nutrient for higher plants. The high-affinity sulfate transporter, SULTR1;2, is localized in the epidermis and cortex of roots, facilitating the initial uptake of sulfate in Arabidopsis. SULTR1;2 gene is up-regulated at the transcriptional level responding to S-deficiency, but little is known about its regulation at the molecular level. To determine the factors involved in S response, we isolated mutants exhibiting altered response of SULTR1;2 gene expression to S-deficiency.
Transgenic Arabidopsis carrying GFP reporter gene under the control of the SULTR1;2 promoter was used as a parental line for mutagenesis. The parental line shows higher GFP fluorescence under S-deficiency than on S-sufficient condition. EMS-mutagenized M2 plants of this transgenic line were screened for mutants with increased level of GFP fluorescence on S-sufficient condition. Several candidates were islated, showing increased mRNA accumulation of both the transgene and endogenous SULTR1;2.
