Role of sugars and organic acids in regulating the concentration and activity of the alternative oxidase in Poa annua roots.
Detached roots of Poa annua were used to study alternative oxidase protein expression upon the addition of sucrose, glucose, fructose, inositol, mannitol, citrate or malate, at a concentration of 1 or 10 mM for 24 h. After 24 h the capacity of cytochrome c oxidase was decreased equally in all treatments. Only citrate induced the expression of the alternative oxidase, especially at a concentration of 1 mM (15-fold). The activity of the alternative pathway (measured with the (18)O-fractionation technique) was not affected by the addition of sucrose for 24 h as compared with time zero. However, after the addition of citrate or mannitol the activity of the alternative pathway decreased to almost zero. The discrepancy between the large increase in alternative oxidase protein concentration when citrate was applied and the concomitant decrease in alternative pathway activity is discussed.
Millenaar
Frank F
FF
Plant Ecophysiology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands. F.F.Millenaar@bio.uu.nl
Gonzalez-Meler
Miquel A
MA
Siedow
James N
JN
Wagner
Anneke M
AM
Lambers
Hans
H
D002241:Carbohydrates / Q000494:pharmacology*; D019343:Citric Acid / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000378:metabolism; D005632:Fructose / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D015151:Immunoblotting; D007294:Inositol / Q000494:pharmacology; D008293:Malates / Q000494:pharmacology; D008353:Mannitol / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D024101:Mitochondrial Proteins; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010940:Plant Proteins; D018517:Plant Roots / Q000187:drug effects* / Q000201:enzymology; D006109:Poaceae / Q000187:drug effects* / Q000201:enzymology; D013367:Submitochondrial Particles / Q000187:drug effects / Q000378:metabolism; D013395:Sucrose / Q000494:pharmacology; D000099188:Alternative Oxidase
D002241:Carbohydrates; D019343:Citric Acid; D003576:Electron Transport Complex IV; D005632:Fructose; D005947:Glucose; D007294:Inositol; D008293:Malates; D008353:Mannitol; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010100:Oxygen; D010940:Plant Proteins; D013395:Sucrose; D000099188:Alternative Oxidase; C030298:malic acid