Abstract
To study the regulations of gene expressions by sulfur deficiency, we previously reported analyses of mutants with altered GFP fluorescence compared to parental transgenic Arabidopsis thaliana line NOB7 expressing green fluorescent protein (GFP) under control of a sulfur-responsive chimeric promoter. In the present study, EMS-mutagenized M2 seeds were grown for ten days and transferred to plates containing 10 mM O-acetyl-L-Ser (OAS), a precursor of Cys. OAS application causes general up-regulations of sulfur-responsive gene expressions. Plants showing altered GFP fluorescence compared to NOB7 plants were selected as putative mutants. Several mutant lines were further analyzed through mappings of the causal genes, quantitations of transcript accumulations of sulfur-responsive genes and analyses of metabolites. One of the mutant lines exhibited reduced GFP fluorescence both under sulfur sufficient or deficient conditions than NOB7. In this mutant, mutations were found in At4g21670, a gene shown to be involved in ABA signaling and development.
