INVESTIGADORES
CARRARI Fernando Oscar
artículos
Título:
Expression of a yeast acetyl-CoA hydrolase in the mitochondrion of tabacco plants inhibits growth and restricts photosynthesis
Autor/es:
BENECH-MACHADO L; BÄUERLEIN M; CARRARI F; SCHAUER N; LYTOVCHENCKO A; GIBON Y; KELLY A; E-LOUREIRO M; MÜLLER-RÖBER B; WILLMITZER L; FERNIE AR
Revista:
PLANT MOLECULAR BIOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2004 p. 645 - 662
ISSN:
0167-4412
Resumen:
Acetyl Coenzyme A (acetyl CoA) is required in the mitochondria to fuel the operation of the Krebs cycle
and within the cytosolic, peroxisomal and plastidial compartments wherein it acts as the immediate pre-
cursor for a wide range of anabolic functions. Since this metabolite is impermeable to membranes it follows
that discrete pathways both for its synthesis and for its utilization must be present in each of these
organelles and that the size of the various compartmented pools are independently regulated. To determine
the specific role of acetyl CoA in the mitochondria we exploited a transgenic approach to introduce a yeast
acetyl CoA hydrolase (EC 3.1.2.1.) into this compartment in tobacco plants. Despite the facts that the
introduced enzyme was correctly targeted and that there were marked reductions in the levels of citrate and
malate and an increase in the acetate content of the transformants, the transgenic plants surprisingly
exhibited increased acetyl CoA levels. The lines were further characterised by a severe growth retardation,
abnormal leaf colouration and a dramatic reduction in photosynthetic activity correlated with a marked
reduction in the levels of transcripts of photosynthesis and in the content of photosynthetic pigments. The
altered rate of photosynthesis in the transgenics was also reflected by a modified carbon partitioning in
leaves of these lines, however, further studies revealed that this was most likely caused by a decreased
source to sink transport of carbohydrate. In summary these results suggest that the content of acetyl CoA is
under tight control and that alterations in the level of this central metabolite have severe metabolic and
developmental consequences in tobacco.