Regulation of sulfur-responsive gene expression by exogenously applied cytokinins in Arabidopsis thaliana.

Effects of plant hormones on a sulfur-deficiency responsive element (betaSR) from the promoter region of the beta subunit gene of beta-conglycinin, a major seed storage protein of soybean, were investigated using transgenic Arabidopsis thaliana. Among the hormones tested, the cytokinins, trans-zeatin (Z) and trans-zeatin riboside, upregulated gene expression directed by the betaSR element both in the presence and in the absence of sulfate in the medium. Z also increased transcript accumulation of two endogenous sulfur-responsive genes, the adenosine 5'-phosphosulfate reductase (APR1) and the Sultr2;2, a sulfate transporter.

Differential tissue-specific response to sulfate and methionine of a soybean seed storage protein promoter region in transgenic Arabidopsis.

Expression of the gene encoding the beta subunit of beta-conglycinin, a major soybean seed storage protein, is upregulated by sulfur deficiency and downregulated by methionine (Met). The tissue-specificity of these regulatory mechanisms was studied using a sulfate-responsive region (beta(SR)) from the beta subunit gene promoter. Transgenic Arabidopsis thaliana lines were generated carrying a green fluorescent protein (GFP) reporter gene under control of the cauliflower mosaic virus 35S RNA promoter with a tandem repeat of the beta(SR) element, referred to as the P35S::beta(SR)x3: GFP transgene.