Expression of genes related to nitrogen metabolism in maize grown under organic and inorganic nitrogen supplies

• Published in: Soil science and plant nutrition (Tokyo) 2015-03, Vol.61 (2), p.275-280
• Main Authors: Guo, Song, Sun, Wen-yan, Gu, Ri-liang, Zhao, Bing-qiang, Yuan, Li-xing, Mi, Guo-hua
• Format: Article
• Language: English
• Subjects: Assimilation; Biological assimilation; Corn; Crop yield; filling period; gene expression; gene expression regulation; Gene regulation; Genes; grain yield; inorganic and organic nitrogen; Leaves; maize; Metabolism; N assimilation and remobilization; N utilization efficiency; Nitrogen; Nitrogen metabolism; Organic nitrogen; pollution; Zea mays
• ISSN: 1747-0765; 0038-0768; 1747-0765
• DOI: 10.1080/00380768.2014.970117

Application of organic nitrogen (N) has been proposed as a method to reduce potential environmental pollution due to N loss without sacrificing grain yield. The mechanism responsible for organic N regulation of maize (Zea mays L.) N metabolism is nonetheless largely unknown. In this study, we compared the expression of genes related to N assimilation and remobilization during the grain filling stage in maize plants grown under field conditions. We applied five different N treatments, which consisted of N supplied in organic and/or inorganic forms at the following rates: 0/45, 0/120, 0/240, 120/120, and 240/0 kg ha ⁻¹ organic/inorganic N. Yield was found to increase with increasing N input, but no significant difference was found in grain yield among 0/240, 240/0 and 120/120 treatments. Organic N application tended to decrease N accumulation and to increase N utilization efficiency. Genes related to N assimilation activity in leaves, such as ZmNR1 and ZmFd-GOGAT1 , were unaffected by different N forms. In contrast, genes related to N remobilization activity in leaves, such as ZmGS1.1 and ZmGDH1 , were up-regulated, especially in old leaves, by the pure organic N supply treatment (240/0). These data suggest that application of pure organic N likely induces a N-deficiency response in maize plants, with a consequent increase in physiological N utilization efficiency due to up-regulation of key genes involved in N remobilization processes.