title: Overexpression of the 16-kDa α-amylase/trypsin inhibitor RAG2 improves grain yield and quality of rice.
abstract: Increasing grain yield and improving grain quality are two important goals for rice breeding. A better understanding of the factors that contribute to the overall grain quantity and nutritional quality of rice will lay the foundation for developing new breeding strategies. RAG2 is a member of 14-to-16-kDa α-amylase/trypsin inhibitors in rice, which belong to the albumin of seed storage proteins. We found that RAG2 was specifically expressed in ripening seed and its transcription peak was between 14 and 21 days after flowering. Grain size and 1000-grain weight were obviously increased in RAG2-overexpressed lines compared with wild type, and grain size was reduced in RAG2-suppressed lines. In addition, the major storage substances of the seeds differed significantly in RAG2-overexpressed and RAG2-suppressed lines compared to wild type. The protein content and amount of total lipids were increased and decreased, respectively, in the seeds of RAG2-overexpressed and RAG2-suppressed lines. Overexpression of RAG2 significantly increased grain size and improved grain quality and yield simultaneously. These results imply that RAG2 might play an important role in regulating grain weight and seed quality of rice. The functional characterization of rice RAG2 facilitates a further understanding of the mechanisms involved in grain size and seed quality and may be helpful in improving grain yield and quantity in cereal crops.
authors: College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors: Wei
authors: W
authors: Zhou
authors: College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors: Xin
authors: X
authors: Wang
authors: College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors: Dan
authors: D
authors: Zhou
authors: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, China.
authors: Yidan
authors: Y
authors: Ouyang
authors: College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors: Jialing
authors: J
authors: Yao
mesh_terms: D052179:Antigens, Plant / Q000737:chemistry* / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics*; D030821:Plants, Genetically Modified; D055314:Seed Storage Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics* / Q000254:growth & development; D000516:alpha-Amylases / Q000037:antagonists & inhibitors
chemical_list: D052179:Antigens, Plant; D010940:Plant Proteins; C079480:RAG2 protein, Oryza sativa; D055314:Seed Storage Proteins; D000516:alpha-Amylases
keywords: 
  Oryza sativa
  ; 
  RAG2
  ; grain quality; grain weight; seed storage proteins