Overexpression of the maize ZmAMT1;1a gene enhances root ammonium uptake efficiency under low ammonium nutrition

• Published in: Plant biotechnology reports Vol. 12; no. 1; pp. 47 - 56
• Main Authors: Zhao, Yang, Liu, Zhi, Duan, Fengying, An, Xia, Liu, Xiangguo, Hao, Dongyun, Gu, Riliang, Wang, Zhangkui, Chen, Fanjun, Yuan, Lixing
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.02.2018; Springer Nature B.V; 한국식물생명공학회
• Subjects: Affinity; Agriculture; Ammonium; Biomedical and Life Sciences; Biotechnology; Cell Biology; Corn; Cultivars; Gene expression; Life Sciences; Nitrogen; Nutrition; Original Article; Plant Biochemistry; Plant Sciences; Post-translation; Proteins; Roots; Transgenic plants; 농학; AMT; Nitrogen use efficiency; Post-translational regulation; Transgenic plants; Ammonium uptake
• ISSN: 1863-5466; 1863-5474
• DOI: 10.1007/s11816-018-0471-1

High-affinity ammonium uptake in maize roots is mainly mediated by AMT1-type ammonium transporters ZmAMT1;1a and ZmAMT1;3, but whether the increased expression of ZmAMTs genes is able to enhance ammonium uptake capacity and subsequently improves overall nitrogen use efficiency remains to be elucidated. In this work, ZmAMT1;1a -overexpression transgenic maize plants were generated with the elevated levels of transcripts and proteins, and phenotypically analyzed together with wild-type plants grown in nutrient solution under two regimes of ammonium supply. Under low ammonium nutrition (0.04 mM), in relative to wild-type plants, the maize transgenic lines showed an approximately 17% increases in the high-affinity ammonium uptake capacity of roots as revealed by 15 N-labeled ammonium influx assay and further contributed to about 7% increases in the total nitrogen uptake at the whole plant level. By contrast, when ammonium was supplied in high amounts (1 mM), wild-type plants expressed higher levels of ZmAMT1;1a, but exhibited a lower ammonium uptake capacity in roots. Furthermore, the transgenic maize line accumulated more amounts of ZmAMT1;1a protein, but did not translate into an enhanced ammonium acquisition, suggesting a possible post-translational down-regulation of ZmAMT1;1a by high ammonium. This study proved the possibility to enhance ammonium acquisition by elevating ZmAMTs expression in maize roots and provided an effective transgenic approach on developing high nitrogen use efficient maize cultivars.