Reference : Biosynthesis of peroxidases: a role as interplay between primary and hormonal metabolisms
Parts of books : Contribution to collective works
Life sciences : Phytobiology (plant sciences, forestry, mycology...)
http://hdl.handle.net/2268/4037
Biosynthesis of peroxidases: a role as interplay between primary and hormonal metabolisms
English
Gaspar, Thomas mailto [> > Botanique, radiobotanique & serres expér. >]
Le Dily, Frédérique [Université de Caen Basse-Normandie > > Physiologie et Biochimie Végétales > >]
Billard, Jean-Pierre [Université de Caen Basse-Normandie > > Physiologie et Biochimie Végétales > >]
Huault, Claude [Université de Caen Basse-Normandie > > Physiologie et Biochimie Végétales > >]
Bisbis, Badia [Université de Liège - ULiège > > Hormonologie végétale > >]
Kevers, Claire mailto [Université de Liège - ULiège > Département des sciences de la vie > Biologie moléculaire et biotechnologie végétales >]
Dommes, Jacques mailto [Université de Liège - ULiège > Département des sciences de la vie > Biologie moléculaire et biotechnologie végétales >]
2002
Plant perodixases - Biochemistry and physiology - VI international plant peroxidase symposium Proceedings
Acosta, M.
Rodriguez-lopez, J.-N.
Pedreno, Maria-A
servicio de publicationes. Universidad de Murcia
169-185
84-8371-379-9
Murcia
Spain
[en] Hyperhydric, fully habituated (growth independent from exogenous auxin and cytokinin), fully heterotrophic (achlorophyllous, dependent on sucrose supply, nevertheless able to fix CO2 non-photosynthetically) and non-organogenic (complete loss of any organogenic totipotency) sugarbeet cells in culture were characterized by a very low peroxidase activity, among other deficient heme compounds. This deficiency resulted from the lack of synthesis of the precursor aminolevulinic acid (ALA) through the chloroplastic Beale pathway; the low productive unusual ALA synthesis through the mitochondrial Shemin pathway (commonly used by animals and fungi) functioned but further at a limited rate due to inhibition of ALA-dehydratase by benzoic derivatives, predominant among the phenolic acids of these cells (compared to normal ones). A thorough investigation of the metabolic and hormonal functioning of these neoplastic cells showed that the above deviation originated from a disturbed nitrogen metabolism that diverted glutamate from the Kreb's cycle into polyamine (over) synthesis, which had also as consequence a low ethylene production. The Kreb's cycle could be replenished by oxaloacetate and malate deriving from the anaplerotic fixation of CO2 onto phosphoenolpyruvate. A privileged pentose phosphate pathway (PPP) allowed the formation of substrates for a non-limited biosynthesis of (endogenous) auxins and cytokinins. The PPP, through NAD(P)H formation, enhanced nitrogen metabolism, but also, together with a putative H2O2 accumulation (originated from high superoxide dismutase activity and high polyamine oxidation combined with low catalase activity), favoured the alternative respiratory pathway. These results not only illustrate a novel view of integration of hormonal metabolisms with the C and N primary and secondary ones but also allow to consider the biosynthesis of peroxidases in an interplay or mediating role between them.
Researchers
http://hdl.handle.net/2268/4037

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