A possible role for pyrophosphate in the coordination of cytosolic and plastidial carbon metabolism within the potato tuber.
Plant Physiol
; 123(2): 681-8, 2000 Jun.
Article
en En
| MEDLINE
| ID: mdl-10859198
ABSTRACT
The early stages of tuber development are characterized by cell division, high metabolic activity, and the predominance of invertase as the sucrose (Suc) cleaving activity. However, during the subsequent phase of starch accumulation the cleavage of Suc occurs primarily by the action of Suc synthase. The mechanism that is responsible for this switch in Suc cleaving activities is currently unknown. One striking difference between the invertase and Suc synthase mediated cleavage of Suc is the direct involvement of inorganic pyrophosphate (PPi) in the latter case. There is presently no convincing explanation of how the PPi required to support this process is generated in potato (Solanum tuberosum) tubers. The major site of PPi production in a maturing potato tubers is likely to be the reaction catalyzed by ADP-glucose pyrophosphorylase, the first committed step of starch biosynthesis in amyloplasts. We present data based on the analysis of the PPi levels in various transgenic plants altered in starch and Suc metabolism that support the hypothesis that PPi produced in the plastid is used to support cytosolic Suc breakdown and that PPi is an important coordinator of cytosolic and plastidial metabolism in potato tubers.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Solanum tuberosum
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Carbono
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Plastidios
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Difosfatos
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Citosol
Idioma:
En
Revista:
Plant Physiol
Año:
2000
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
EEUU
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ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA