Functional Analysis of a Wheat AGPase Plastidial Small Subunit with a Truncated Transit Peptide

Yang Yang; Tian Gao; Mengjun Xu; Jie Dong; Hanxiao Li; Pengfei Wang; Gezi Li; Tiancai Guo; Guozhang Kang; Yonghua Wang

doi:10.3390/molecules22030386

Functional Analysis of a Wheat AGPase Plastidial Small Subunit with a Truncated Transit Peptide

Molecules. 2017 Mar 1;22(3):386. doi: 10.3390/molecules22030386.

Authors

Yang Yang¹, Tian Gao², Mengjun Xu³, Jie Dong⁴, Hanxiao Li⁵, Pengfei Wang⁶, Gezi Li⁷, Tiancai Guo⁸, Guozhang Kang⁹, Yonghua Wang^{10

11}

Affiliations

¹ The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China. yangyang91@henau.edu.cn.
² The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China. gaotian1211@henau.edu.cn.
³ The National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou 450002, China. mengjunxu920304@henau.edu.cn.
⁴ The National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou 450002, China. dongjie@henau.edu.cn.
⁵ The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China. xxhong@henau.edu.cn.
⁶ The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China. wangpf@henau.edu.cn.
⁷ The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China. ligezi@henau.edu.cn.
⁸ The National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou 450002, China. gtcwheat@henau.edu.cn.
⁹ The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China. guozhangkang@henau.edu.cn.
¹⁰ The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou 450002, China. wangyonghua88@henau.edu.cn.
¹¹ The National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China. wangyonghua88@henau.edu.cn.

Abstract

ADP-glucose pyrophosphorylase (AGPase), the key enzyme in starch synthesis, consists of two small subunits and two large subunits with cytosolic and plastidial isoforms. In our previous study, a cDNA sequence encoding the plastidial small subunit (TaAGPS1b) of AGPase in grains of bread wheat (Triticum aestivum L.) was isolated and the protein subunit encoded by this gene was characterized as a truncated transit peptide (about 50% shorter than those of other plant AGPS1bs). In the present study, TaAGPS1b was fused with green fluorescent protein (GFP) in rice protoplast cells, and confocal fluorescence microscopy observations revealed that like other AGPS1b containing the normal transit peptide, TaAGPS1b-GFP was localized in chloroplasts. TaAGPS1b was further overexpressed in a Chinese bread wheat cultivar, and the transgenic wheat lines exhibited a significant increase in endosperm AGPase activities, starch contents, and grain weights. These suggested that TaAGPS1b subunit was targeted into plastids by its truncated transit peptide and it could play an important role in starch synthesis in bread wheat grains.

Keywords: AGPase; Triticum aestivum L.; plastidial small subunit; starch.

MeSH terms

Glucose-1-Phosphate Adenylyltransferase / chemistry
Glucose-1-Phosphate Adenylyltransferase / metabolism*
Peptides / metabolism*
Plastids / metabolism*
Protein Subunits / chemistry
Protein Subunits / metabolism*
Protein Transport
Proteolysis
Recombinant Fusion Proteins
Triticum / metabolism*

Substances

Peptides
Protein Subunits
Recombinant Fusion Proteins
Glucose-1-Phosphate Adenylyltransferase