Effect of ATP Sulfurylase Overexpression in Bright Yellow 2 Tobacco Cells1 Regulation of ATP Sulfurylase and SO

• Published in: Plant physiology (Bethesda) Vol. 116; no. 4; pp. 1307 - 1313
• Main Authors: Hatzfeld, Yves, Cathala, Nicole, Grignon, Claude, Davidian, Jean-Claude
• Format: Journal Article
• Language: English
• Published: American Society of Plant Physiologists 01.04.1998
• ISSN: 0032-0889; 1532-2548

To determine if the ATP sulfurylase reaction is a regulatory step for the SO 4 2− -assimilation pathway in plants, an Arabidopsis thaliana ATP sulfurylase cDNA, APS2 , was fused to the 35S promoter of the cauliflower mosaic virus and introduced by Agrobacterium tumefaciens -mediated transformation into isolated Bright Yellow 2 tobacco ( Nicotiana tabacum ) cells. The ATP sulfurylase activity in transgenic cells was 8-fold that in control cells, and was correlated with the expression of a specific polypeptide revealed by western analysis using an anti-ATP sulfurylase antibody. The molecular mass of this polypeptide agreed with that for the overexpressed mature protein. ATP sulfurylase overexpression had no effect on [ 35 S]SO 4 2− influx or ATP sulfurylase activity regulation by S availability, except that ATP sulfurylase activity variations in response to S starvation in transgenic cells were 8 times higher than in the wild type. There were also no differences in cell growth or sensitivity to SeO 4 2− (a toxic SO 4 2− analog) between transgenic and wild-type cells. We propose that in Bright Yellow 2 tobacco cells, the ATP sulfurylase derepression by S deficiency may involve a posttranscriptional mechanism, and that the ATP sulfurylase abundance is not limiting for cell metabolism.