Open AccessDEP1 is involved in regulating the carbon–nitrogen metabolic balance to affect grain yield and quality in rice (Oriza sativa L.)
Author(s) -
Mingzhu Zhao,
Mingzhu Zhao,
Shuang Gu,
Jian Sun,
Zhengqiang Ma,
Lili Wang,
Wenjing Zheng,
Zhenbo Xu
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0213504
Subject(s) - panicle , rubisco , agronomy , biology , phosphoenolpyruvate carboxylase , glutamate synthase , glutamine synthetase , nitrogen cycle , grain quality , nitrogen , chemistry , photosynthesis , botany , biochemistry , glutamine , organic chemistry , amino acid
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.