Response of cytosolic-isozyme and plastid-isozyme levels of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase to physiological state of Nicotiana silvestris in suspension culture
Two isozymes of 3-deoxy-D-arabin0-heptulosonate 7-phosphate synthase are partitioned into plastic (DS-Mn) and cytosolic (DS-Co) compartments of at least several higher plants. Differential variation of isozyme levels and in the timing of their expression was observed during growth of Nicotiana silvestris in suspension culture. The ratio of DS-Co to DS-Mn varied about fivefold in comparison of the different physiological stages of growth. Cultures maintained in exponential phase for >10 generations (EE cells) possessed balanced-growth properties and did not exhibit the considerable variation of isozyme levels found during the initial 2 to 3 generations of exponential growth (E cells) that followed subculture of stationary-phase cultures. The plastid isozyme level declined substantially in stationary phase, responded immediately to subculture, and reached a peak in early exponential growth similar to the steady-state level of DS-Mn in EE cells. In contrast, the cytosolic isozyme level peaked in late exponential growth. A recent history of stationary-phase physiology appeared to foster elevated synthesis of DS-Co since the steady-state level of DS-Co in EE cells was much lower than in E cells.
- Research Organization:
- State Univ. of New York, Binghamton
- DOE Contract Number:
- AC02-78ER04967
- OSTI ID:
- 6439952
- Journal Information:
- Plant Physiol.; (United States), Vol. 83:3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evidence from Solanum tuberosum in support of the dual-pathway hypothesis of aromatic biosynthesis
Crystallization and preliminary X-ray crystallographic analysis of 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase from Mycobacterium tuberculosis