CEFOBI   05405
CENTRO DE ESTUDIOS FOTOSINTETICOS Y BIOQUIMICOS
Unidad Ejecutora - UE
capítulos de libros
Título:
Different solutions for the same biochemical problem: provision of CO2 in Bundle Sheath Cells
Autor/es:
MARIA FABIANA DRINCOVICH; LARA, MARÍA VALERIA; MAURINO, VERÓNICA G; ANDREO, CARLOS S
Libro:
C4 photosynthesis and related CO2 concentration mechanisms; Advances in Photosynthesis and Respiration
Editorial:
Advances in Photosynthesis and Respiration (AIPH) Series
Referencias:
Lugar: No Informado; Año: 2009; p. 1 - 1
Resumen:
The decarboxylation of C4 acids in the bundle sheath cells (BSCs) of C4-plants is a key step in the photosynthetic process in this type of carbon assimilation. Depending on the particular subtype of C4-species, this process can be mediated by different enzymes: NADP-malic enzyme (NADP-ME), NAD-malic enzyme (NAD-ME) and/or Phosphoenolpyruvate carboxykinase (PEPCK), and each enzyme has a different subcellular compartmentalization within the BSCs. Thus, the C4 subtype cycle mediated by each decarboxylase displays distinguishing features in leaf anatomy, biochemistry and physiology in various families having C4 species. In some cases among C4 plants, the operation of more than one type of decarboxylating enzyme in the C4 photosynthetic process has been assessed. During the last few years, remarkable advances have been made in the characterization of different isoforms of each C4 decarboxylase. In most cases, non-photosynthetic isoforms of the C4-decarboxylating enzymes involved in primary and/or secondary metabolisms were characterized. These non-C4 isoforms were for sure the starting point for the evolution of the C4-specific decarboxylases, gaining characteristics that make them more suitable to fulfill the requirements of the photosynthetic process. For each decarboxylating enzyme, the analysis of phylogenetic relationships reveals several features of the molecular evolution of the C4 process which accomplished the same biochemical feature: generation of CO2 around Rubisco in BSCs, preventing photorespiration and enhancing photosynthesis