DEP1 is involved in regulating the carbon-nitrogen metabolic balance to affect grain yield and quality in rice (Oriza sativa L.)

• Published in: PloS one Vol. 14; no. 3; p. e0213504
• Main Authors: Zhao, Mingzhu, Zhao, Minghui, Gu, Shuang, Sun, Jian, Ma, Zuobin, Wang, Lili, Zheng, Wenjing, Xu, Zhengjin
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 11-03-2019; Public Library of Science (PLoS)
• Subjects: Agricultural production; Amino acids; Analysis; Biochemistry; Biology and Life Sciences; Carbohydrates; Carbon; Carbon - metabolism; Carbon dioxide; Carbon/nitrogen ratio; Construction; Crop yield; Crop yields; Edible Grain - genetics; Edible Grain - growth & development; Edible Grain - metabolism; Engineering and Technology; Fertilizers; Gene expression; Gene Expression Regulation, Plant; Genes; Genetic aspects; Genetic engineering; Glutamate; Glutamate-ammonia ligase; Glutamine; Grain size; Growth conditions; Leaves; Ligases; Metabolism; Metabolites; Monosaccharides; Nitrogen; Nitrogen - metabolism; Oryza; Oryza - genetics; Oryza - growth & development; Oryza - metabolism; Oxygenase; Phosphates; Phosphoenolpyruvate carboxylase; Physical Sciences; Physiological aspects; Physiology; Plant genetic engineering; Plant metabolites; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified - genetics; Plants, Genetically Modified - growth & development; Plants, Genetically Modified - metabolism; Proteins; Quality; Research and Analysis Methods; Ribulose-1,5-bisphosphate; Ribulose-bisphosphate carboxylase; Rice; Sheaths; Straw; Studies; Transgenic plants; Up-Regulation; Weight; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0213504

The DEP1 (dense and erect panicle 1) gene, which corresponds to the erect panicle architecture, shows a pleiotropic effect in increasing grain yield and nitrogen use efficiency (NUE) in rice. Nevertheless, it remains unclear whether the carbon-nitrogen metabolic balance changes as the dep1 allele enhances nitrogen uptake and assimilation. In this study, we generated transgenic Akitakomati plants by overexpressing dep1 and analyzed the carbon-nitrogen metabolic status, gene expression profiles, and grain yield and quality. Under either low or high nitrogen growth conditions, the carbon-nitrogen metabolic balance of dep1-overexpressed lines was broken in stem sheaths and leaves but not in grains; the dep1-overexpressed plants showed higher expressions of glutamine synthetase (GS) and glutamate synthase (GOGAT) genes than the wildtype, along with increased total nitrogen and soluble protein content in the straw at maturity. However, the ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) and phosphoenolpyruvate carboxylase (PEPC) genes were downregulated in dep1-overexpressed plants, leading to a decreased carbohydrate content and carbon/nitrogen ratio. Although the unbalanced carbon-nitrogen metabolism decreased the grain-filling rate, grain setting percentage, 1000 grain weight, and grain quality in dep1-overexpressed lines, it led to increased grain numbers per panicle and consequently increased grain yield. Our results suggest that an unbalanced carbon-nitrogen metabolic status is a major limiting factor for further improving grain yield and quality in erect panicle varieties.