Control of ascorbate synthesis by respiration and its implications for stress responses

MILLAR AH; MITTOVA V; KIDDLE G; HEAZLEWOOD JL; BARTOLI CG; THEODOULOU FL; FOYER CH

PLANT PHYSIOLOGY.

American Society of Plant Biologists

Lugar: Rockville; Año: 2003 vol. 133 p. 443 - 447

0032-0889

The aim of this work was to evaluate the inter-relationship between L-galactone-1,4-lactone dehydrogenase (GalLDH) and the mitochondrial Complex I. Proteomic techniques have revealed that GALDH is physically associated to a minor high mobility form of the complex I. Rotenone, a specific inhibitor of complex I, inhibits ascorbic acid (AA) synthesis rate to the same degree as KCN. When electrons are introduced only via GL to cytochrome c (by adding no substrate other than L-galactone lactone), there is no effect of added rotenone on AA synthesis rate, but the rate of AA synthesis is lower than when complex I is operating. This strongly suggests that electron flow through complex I affects AA synthesis rate and that this electron flow is required for optimal rates of AA synthesis.