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pH and carbon supply control the expression of phosphoenolpyruvate carboxylase kinase genes in Arabidopsis thaliana
Author(s) -
CHEN ZHIHUI,
JENKINS GARETH I.,
NIMMO HUGH G.
Publication year - 2008
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2008.01885.x
Subject(s) - phosphoenolpyruvate carboxylase , phosphoenolpyruvate carboxykinase , gene expression , biochemistry , arabidopsis , intracellular , kinase , phosphorylation , biology , gene , pyruvate carboxylase , arabidopsis thaliana , psychological repression , chemistry , enzyme , mutant
Phosphoenolpyruvate carboxylase (PEPC) is thought to play many roles in C 3 plants including the provision of biosynthetic precursors and control of pH during N assimilation. Its activity is controlled via phosphorylation catalysed by PEPC kinases, which are encoded by PPCK genes. We examined PPCK expression in response to changes in the supply of N or C, and to changes in intracellular pH, using cultured Arabidopsis cells and seedlings. The results show that expression of both PPCK1 and PPCK2 is increased by C availability, but does not respond to N availability. Expression of the two PPCK genes and the phosphorylation state of PEPC are increased in response to increasing intracellular pH. Elevated pH also reduces the repression of PPCK gene expression by P i . Expression of phosphoenolpyruvate carboxykinase (PEPCK), which catalyses the decarboxylation of oxaloacetate, is decreased in response to increasing intracellular pH. pH homeostasis may be mediated at least partly by reciprocal changes in the expression of PPCK genes and PEPCK.