Ishimaru K, Kobayashi N, Ono K, Yano M, Ohsugi R
National Institute of Agrobiological Sciences, 2-1-2, Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
J Exp Bot. 2001 Sep;52(362):1827-33. 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 Nipponbarexindica 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.
利用粳稻品种日本晴与籼稻品种卡萨拉斯构建的回交自交系群体，通过数量性状基因座（QTL）分析，研究了水稻叶片中核酮糖-1,5-二磷酸羧化酶（Rubisco）含量、可溶性蛋白含量与叶片总氮（N）含量之间的遗传关系。叶片中Rubisco与总叶氮的比值是提高植物光合氮利用效率的主要目标。在总叶氮含量的QTL附近未检测到控制Rubisco含量的QTL。这些结果表明，Rubisco含量和总叶氮含量受不同基因控制。检测到了控制Rubisco与总叶氮比值（CORNs）的QTL。这些结果表明在决定该比值时可能涉及某些机制，而Rubisco和总叶氮的含量则以其他方式控制。在优良回交自交系中，Rubisco与总叶氮的比值高于双亲。这些结果表明通过CORNs提高栽培稻氮利用效率具有很大可能性。在抽穗后5天，一个控制Rubisco含量的QTL定位在第8染色体上一个控制可溶性蛋白含量的QTL附近；在抽穗后25天，该QTL定位在第9染色体上。在每个染色体区域，两个QTL的峰值精确重叠，同一基因产生多效性的可能性很高。在抽穗后5天或25天检测到的控制可溶性蛋白或Rubisco的QTL不同。这表明这些性状的遗传控制取决于叶片的生长阶段。
