Regulation of alternative oxidase activity during phosphate deficiency in bean roots (Phaseolus vulgaris).

摘要: Cyanide-resistant respiration was studied in mitochondria isolated from the roots of bean plants (Phaseolus vulgaris L. cv. Zlota Saxa) grown hydroponically up to 16 days on a phosphate-sufficient (+P, control) or phosphate-deficient (-P) medium. Western blotting indicated that alternative oxidase (AOX) present only its reduced (active) form, both and roots, but latter, amount AOX protein greater. Addition pyruvate isolation, washing reaction media made +P cyanide-insensitive, similar -P roots. The doubled activity NAD-malic enzyme (NAD-ME) compared with root may suggest increased production mitochondria. Lower cytochrome c (COX) no uncoupler effect limited chain In mitochondria, oxygen uptake decreased level Q reduction 60 80%. With (AOX not fully activated), inhibition pathway resulted an ratio ubiquinone (Qr) total (Qt) (Qr/Qt) did change Qr/Qt When present, kinetics for were It is suggested participation provide acclimation phosphate deficiency. Stabilization by might prevent harmful formation reactive species.