| Autor: |
Godt, Dietmute E., Riegel, Angelika, Roitsch, Thomas |
| Zdroj: |
Journal of Plant Physiology; June 1995, Vol. 146 Issue: 3 p231-238, 8p |
| Abstrakt: |
The effect of source/sink modifications on the enzyme activity and on the steady state level of mRNA of sucrose synthase has been analyzed in Chenopodium rubrum. A sucrose synthase cDNA with high homology to sucrose synthases from both monocotyledonous and dicotyledonous plants has been cloned and used as a homologous probe for Northern blot analyses. Photoautotrophic suspension culture cells, which may be shifted to mixotrophic growth by adding sugars, have been used as a model system to investigate the transition between autotrophic and heterotrophic growth. The higher activity of sucrose synthase after preincubation in the presence of D-glucose, D-fructose or sucrose correlates with an elevated level of mRNA. The sucrose synthase gene was fully induced above a concentration of 20 mM glucose and the steady state level of mRNA was already elevated 1 h after the addition of glucose. Induction of sucrose synthase by 6-desoxyglucose suggests that the non-phosphorylated glucose is the signal for the sugar induced gene expression. Both the enzyme activity and the mRNA level showed a sink tissue specific distribution in plants. The data suggest that sucrose synthase is important both for sink metabolism and the source sink transition. |
| Databáze: |
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