2004 Fiscal Year Final Research Report Summary
Nitrogen Recycling System Analyzed by Molecular Physiology together with QTL Analysis in Rice
| Project/Area Number |
14360035
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Plant nutrition/Soil science
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
YAMAYA Tomoyuki Tohoku University, Graduate School of Agricultural Science, Professor, 大学院・農学研究科, 教授 (30144778)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SATO Tadashi Tohoku University, Graduate School of Life Science, Associate Professor, 大学院・生命科学研究科, 助教授 (40134043)
|
|---|
| Project Period (FY) |
2002 – 2004
|
| Keywords | rice / QTL Analysis / Nitrogen Recycling / Chromosome-substituted lines / Panicle Weight / Tiller / Glutamine Svnthetase / DNA Markers |
|---|
| Research Abstract |
A quantitative trait locus (QTL) associated with the protein content of cytosolic glutamine synthetase (GS1 ; EC 6.3.1.2) in senescing leaves, panicle number and panicle weight was characterized in rice (Oryza sativa L.). A nearly isogenic line (NIL), C-22, developed by marker-assisted selection was grown under different nitrogen levels in a greenhouse and in a paddy field. C-22 had a small segment (approximately 50 cM) substituted from the Kasalath chromosome in chromosome 2 on a Koshihikari genetic background. C-22 showed a 12-37% lower content of GS1 protein in leaf blades than Koshihikari, which was in good agreement with a QTL region positively affected by the japonica chromosome. At an early vegetative stage, C-22 had more active tillers than Koshihikari in the greenhouse. At the reproductive stage, both panicle number and total panicle weight of C-22 were significantly higher than those of Koshihikari, particularly when grown with a low-nitrogen condition. These traits of C-22 were further confirmed in a paddy field. Thus, development of tillers was positively affected by the Kasalath chromosome at an early vegetative stage, which increased the panicle number and panicle weight at the mature stage in C-22. These data indicate that the target QTL (Pnn1 ; panicle number 1) is important in the development of tillers and panicles in rice. Pnn1 was delimited at the 6.7 cM region, demonstrating that developing tiller formation in the 2nd axil (RDT ; ratio of developing tillers formation in the 2nd axil) was determined using substituted lines. This QTL region has been successively narrowed down to 23 kb using various substituted lines of Kasalath chromosome.
Physiological function of GS1 ; 1 has been investigated using knock-out mutants of GS1 ; 1 gene and this result will be published in Plant Journal. In addition, function of PII-like protein that would be expected to be involved in the Gln signaling has also been published.
|
