1991 Fiscal Year Final Research Report Summary
The regulation of PEP carboxylase gene expression by nitrogen in maize leaf tissue
| Project/Area Number |
02454010
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
植物生理学
|
|---|
| Research Institution | Nagoya University |
|---|
Principal Investigator |
SUGIYAMA Tatsuo Nagoya University, School of Agriculture, Department of Agricultural Chemistry, Professor, 農学部, 教授 (50023453)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HASE Toshiharu Nagoya university, School of Agriculture, Department of Agricultural Chemistry,, 農学部, 助教授 (00127276)
|
|---|
| Project Period (FY) |
1990 – 1991
|
| Keywords | Maize (Zea mays L.) / PEP carboxylase / Carbonic anhydrase / Glutamin synthetase / Glutamate synthase / Regulation of Gene expression by nitrogen / C4-photosynthesis genes / cytokinin |
|---|
| Research Abstract |
The following results were obtained by analyzing metabolic intermediates, enzyme activities, proteins, and mRNAs in the basal region of leaves, namely, photosynthetically maturing cells, of maize plants during recovery from N-stress.
(A)The selective accumulation of PEP carboxylase(PEPC)is regulated primarily at transcriptional level in responding to N-availability. The N-avaialbility for induction of the N-dependent gene expression of PEPC was studied. The results obtained indicate that glutamine can be a positive signal for the control of the N-dependent gene expression of PEPC. The results also suggested that the accumulation of glutamine is mainly due to the differential expression of glutamine synthetase and ferredoxin-dependent-glutamate synthase during recovery from N-stress.
(B)In addition to N-source cytokinin is an essential component for the induction of PEPC gene in the detached leaves of N-stressed plants, showing a hormonal specificity.
(C)The gene expression of carbonic anhydrase(CA), a core enzyme in the C4pathway of photosynthesis, was analyzed in comparison to that of PEPC during recovery from N-stress. The results obtained show that CA and PEPC are coordinately regulated by the same or very similar mechanism in responding to N-availability.
(D)The gene expression of glutamine synthetase located in the cytosols of mesophyil and bundle sheath cells was examined under various N-conditions. However, the levels of MRNA encoding for this enzyme unchanged regardless of N condition. This indicates that the N-dependent regulation of gene expression is specific at least for PEPC and CA genes.
|
