title: Development of high-lysine rice via endosperm-specific expression of a foreign LYSINE RICH PROTEIN gene.
abstract: Lysine (Lys) is considered to be the first limiting essential amino acid in rice. Although there have been extensive efforts to improve the Lys content of rice through traditional breeding and genetic engineering, no satisfactory products have been achieved to date.
  
  
  
  We expressed a LYSINE-RICH PROTEIN gene (LRP) from Psophocarpus tetragonolobus (L.) DC using an endosperm-specific GLUTELIN1 promoter (GT1) in Peiai64S (PA64S), an elite photoperiod-thermo sensitive male sterility (PTSMS) line. The expression of the foreign LRP protein was confirmed by Western blot analysis. The Lys level in the transgenic rice seeds increased more than 30 %, the total amount of other amino acids also increased compared to wild-type. Persistent investigation of amino acids in 3 generations showed that the Lys content was significantly increased in seeds of transgenic rice. Furthermore, Lys content in the hybrid of the transgenic plants also had an approximate 20 % increase compared to hybrid control. At the grain-filling stage, we monitored the transcript abundance of many genes encoding key enzymes involved in amino acid metabolism, and the results suggested that reduced amino acid catabolism led to the accumulation of amino acids in the transgenic plants. The genetically engineered rice showed unfavorable grain phenotypes compared to wild-type, however, its hybrid displayed little negative effects on grain.
  
  
  
  Endosperm-specific expression of foreign LRP significantly increased the Lys content in the seeds of transgenic plant, and the the Lys increase was stably heritable with 3 generation investigation. The hybrid of the transgenic plants also showed significant increases of Lys content in the seeds. These results indicated that expression of LRP in rice seeds may have promising applications in improving Lys levels in rice.
authors.affiliation: Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, China.
authors.forename: Cuicui
authors.initials: C
authors.lastname: Zhang
authors.affiliation: UGC-AoE Plant and Fungal Biotechnology Center, Department of Biology, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Xiurong
authors.initials: X
authors.lastname: Wang
authors.affiliation: UGC-AoE Plant and Fungal Biotechnology Center, Department of Biology, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Qiaoquan
authors.initials: Q
authors.lastname: Liu
authors.affiliation: UGC-AoE Plant and Fungal Biotechnology Center, Department of Biology, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Dingyang
authors.initials: D
authors.lastname: Yuan
authors.affiliation: Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
authors.affiliation: UGC-AoE Plant and Fungal Biotechnology Center, Department of Biology, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Samuel S M
authors.initials: SS
authors.lastname: Sun
authors.affiliation: Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, China. jtu@zju.edu.cn.
authors.forename: Jumin
authors.initials: J
authors.lastname: Tu
mesh_terms: D056625:Endosperm / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D007887:Fabaceae / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D008239:Lysine / Q000032:analysis / Q000378:metabolism*; D012275:Oryza / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D012639:Seeds / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D008239:Lysine
keywords: High-lysine rice; LYSINE RICH PROTEIN (LRP); Lysine; Rice (Oryza sativa L.)