Co-overexpression of genes for nitrogen transport, assimilation, and utilization boosts rice grain yield and nitrogen use efficiency
Jie Luo,
Junnan Hang,
Bilong Wu,
Xilin Wei,
Quanzhi Zhao,
Zhongming Fang
Affiliations
Jie Luo
Institute of Rice Industry Technology Research, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang 550025, Guizhou, China
Junnan Hang
Institute of Rice Industry Technology Research, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang 550025, Guizhou, China
Bilong Wu
Institute of Rice Industry Technology Research, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang 550025, Guizhou, China
Xilin Wei
Institute of Rice Industry Technology Research, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang 550025, Guizhou, China
Quanzhi Zhao
Institute of Rice Industry Technology Research, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang 550025, Guizhou, China
Zhongming Fang
Institute of Rice Industry Technology Research, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang 550025, Guizhou, China; Center of Applied Biotechnology, Wuhan University of Bioengineering, Wuhan 430415, Hubei, China; Corresponding author.
Nitrogen (N) fertilization is necessary for obtaining high rice yield. But excessive N fertilizer reduces rice plant N efficiency and causes negative effects such as environmental pollution. In this study, we assembled key genes involved in different nodes of N pathways to boost nitrate and ammonium uptake and assimilation, and to strengthen amino acid utilization to increase grain yield and nitrogen use efficiency (NUE) in rice. The combinations OsNPF8.9a × OsNR2, OsAMT1;2 × OsGS1;2 × OsAS1, and OsGS2 × OsAS2 × OsANT3 optimized nitrate assimilation, ammonium conversion, and N reutilization, respectively. In co-overexpressing rice lines obtained by co-transformation, the tiller number, biomass, and grain yield per plant of the OsAMT1;2 × OsGS1;2 × OsAS1-overexpressing line exceeded those of wild-type ZH11, the OsNPF8.9a × OsNR2 × OsGS1;2 × OsAS1-overexpressing line, and the OsGS2 × OsAS2 × OsANT3-overexpressing line. The glutamine synthase activity, free amino acids, and nitrogen utilization efficiency (NUtE) of the OsAMT1;2 × OsGS1;2 × OsAS1-overexpressing line exceeded those of ZH11 and other lines that combined key genes. N influx efficiency was increased in the OsAMT1;2 × OsGS1;2 × OsAS1-overexpressing line and OsNPF8.9a × OsNR2 × OsGS1;2 × OsAS1-overexpressing line under a low ammonium and a low nitrate treatment, respectively. We propose that combining overexpression of OsAMT1;2, OsGS1;2, and OsAS1 is a promising breeding strategy for systematically increasing rice grain yield and NUE by focusing on key nodes in the N pathway.
