Are contents of Rubisco, soluble protein and nitrogen in flag leaves of rice controlled by the same genetics?

• Published in: Journal of experimental botany 2001-09, Vol.52 (362), p.1827-1833
• Main Authors: Ishimaru, Ken, Kobayashi, Noriko, Ono, Kiyomi, Yano, Masahiro, Ohsugi, Ryu
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cell and Molecular Biology, Biochemistry and Molecular Physiology; Chromosome Mapping; Chromosomes; Corn; Crosses, Genetic; Fundamental and applied biological sciences. Psychology; Genes, Plant; Genetics and breeding of economic plants; Leaves; Metabolism; Metabolism. Physicochemical requirements; Nitrogen; Nitrogen - metabolism; Oryza - genetics; Oryza - metabolism; Oryza sativa; Oryza sativa (rice); Phenotypic traits; Plant genetics; Plant Leaves - genetics; Plant Leaves - metabolism; Plant physiology; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; Quantitative trait loci; quantitative trait loci (QTL); Quantitative Trait, Heritable; Ribulose-Bisphosphate Carboxylase - genetics; Ribulose-Bisphosphate Carboxylase - metabolism; Rice; Rubisco; Solubility; Varietal selection. Specialized plant breeding, plant breeding aims; Yield, quality, earliness, varia
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jexbot/52.362.1827

Genetic relations among the contents of Rubisco, soluble protein and total leaf nitrogen (N) in leaves of rice (Oryza sativa L.) were studied by quantitative trait loci (QTL) analysis with a population of backcross inbred lines (BILs) of japonica Nipponbare×indica Kasalath. The ratio of Rubisco to total leaf N in leaves is the main target in improving photosynthetic N‐use efficiency in plants. QTLs controlling Rubisco content were not detected near QTLs for total leaf N content. These results indicate that contents of Rubisco and total leaf N are controlled by different genetics. QTLs that controlled the ratio of Rubisco to total leaf N (CORNs) were detected. These results suggest that some mechanism(s) may be involved in determining this ratio, while the contents of Rubisco and total leaf N are controlled in other ways. In elite BILs, the ratios of Rubisco to total leaf N were higher than those of both parents. These results suggest a good possibility of improving N‐use efficiency by CORNs in cultivated rice. A QTL controlling Rubisco content was mapped near a QTL for soluble protein content on chromosome 8 at 5 d after heading and on chromosome 9 at 25 d. In each chromosome region, the peaks of both QTLs overlapped accurately, giving a high possibility of pleiotropic effects by the same genes. Different QTLs controlling soluble protein or Rubisco were detected from those detected at 5 d or 25 d after heading. This suggests that these traits are genetically controlled depending on the growth stages of leaves.