title: Biofortification of rice with the essential amino acid lysine: molecular characterization, nutritional evaluation, and field performance.
abstract: Rice (Oryza sativa L.), a major staple crop worldwide, has limited levels of the essential amino acid lysine. We previously produced engineered rice with increased lysine content by expressing bacterial aspartate kinase and dihydrodipicolinate synthase and inhibiting rice lysine ketoglutarate reductase/saccharopine dehydrogenase activity. However, the grain quality, field performance, and integration patterns of the transgenes in these lysine-enriched lines remain unclear. In the present study, we selected several elite transgenic lines with endosperm-specific or constitutive regulation of the above key enzymes but lacking the selectable marker gene. All target transgenes were integrated into the intragenic region in the rice genome. Two pyramid transgenic lines (High Free Lysine; HFL1 and HFL2) with free lysine levels in seeds up to 25-fold that of wild type were obtained via a combination of the above two transgenic events. We observed a dramatic increase in total free amino acids and a slight increase in total protein content in both pyramid lines. Moreover, the general physicochemical properties were improved in pyramid transgenic rice, but the starch composition was not affected. Field trials indicated that the growth of HFL transgenic rice was normal, except for a slight difference in plant height and grain colour. Taken together, these findings will be useful for the potential commercialization of high-lysine transgenic rice.
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Qing-Qing
authors.initials: QQ
authors.lastname: Yang
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province / Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China.
authors.forename: Chang-Quan
authors.initials: CQ
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Man-Ling
authors.initials: ML
authors.lastname: Chan
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China.
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China.
authors.forename: Jin-Zhu
authors.initials: JZ
authors.lastname: Chen
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province / Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China.
authors.forename: Qian-Feng
authors.initials: QF
authors.lastname: Li
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province / Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China.
authors.forename: Heng-Xiu
authors.initials: HX
authors.lastname: Yu
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China.
authors.forename: Ming-Hong
authors.initials: MH
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Samuel Sai-Ming
authors.initials: SS
authors.lastname: Sun
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou, China Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province / Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China qqliu@yzu.edu.cn.
authors.forename: Qiao-Quan
authors.initials: QQ
authors.lastname: Liu
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000378:metabolism; D000072759:Biofortification / Q000379:methods*; D015139:Blotting, Southern; D008239:Lysine / Q000032:analysis / Q000378:metabolism*; D009753:Nutritive Value; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D019655:Quantitative Trait, Heritable; D012639:Seeds / Q000737:chemistry / Q000378:metabolism
chemical_list: D000596:Amino Acids; D008239:Lysine
keywords: Field performance; grain quality; lysine; metabolic engineering; pyramid transgenic line; rice (Oryza sativa L.).