title: Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene.
abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd(2+) uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance.
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhang
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Bojing
authors.initials: B
authors.lastname: Du
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Di
authors.initials: D
authors.lastname: Liu
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China. Electronic address: qixiaoting@cnu.edu.cn.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Qi
mesh_terms: D017398:Alternative Splicing; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002104:Cadmium / Q000737:chemistry*; D027682:Cation Transport Proteins / Q000378:metabolism*; D004247:DNA / Q000032:analysis; D004269:DNA, Bacterial / Q000235:genetics; D018076:DNA, Complementary / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007501:Iron / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D004269:DNA, Bacterial; D018076:DNA, Complementary; C099651:IRT1 protein, Arabidopsis; D012333:RNA, Messenger; C000595082:SR34b protein, Arabidopsis; C036483:T-DNA; D002104:Cadmium; D004247:DNA; D007501:Iron
keywords: Arabidopsis; Cadmium transporter; Splicing factor; mRNA splicing