The induction of microsomal NADPH:cytochrome P450 and NADH:cytochrome b(5) reductases by long-term salt treatment of cotton (Gossypium hirsutum L.) and bean (Phaseolus vulgaris L.) plants.
We studied the effect of salinity on the activity of microsomal NADPH:cytochrome P450 reductase (CPR, EC 1.6.2.4) and NADH:ferricytochrome b(5) oxidoreductase (B5R, EC 1.6.2.2) in two dicotyledonous plant species differing in their sensitivity to salt, cotton (Gossypium hirsutum L. cv Ogosta) and common bean (Phaseolus vulgaris L. cv Dobrujanski 7). A significant inhibition of fresh weight of salt-treated bean plants was observed, while cotton was affected to a much lesser degree. NaCl application resulted in a significant increase in the activity of both reductases, but was more pronounced in salt-tolerant cotton. We suppose that alterations in B5R and CPR activities may be targeted to the maintenance of membrane lipids. Most probably, plants use both enzymes (B5R and CPR) and their respective electron donors (NADH and NADPH) to reduce cytochrome b(5), which can donate reducing equivalents to a series of lipid-modification reactions such as desaturation and hydroxylation.
Brankova
Liliana
L
Department of Regulation of Plant Growth and Development, Acad. M. Popov Institute of Plant Physiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, bl. 21, 1113 Sofia, Bulgaria. l.brankova@abv.bg
Ivanov
Sergei
S
Alexieva
Vera
V
D042966:Cytochrome-B(5) Reductase / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D003368:Gossypium / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D008861:Microsomes / Q000201:enzymology*; D009251:NADPH-Ferrihemoprotein Reductase / Q000235:genetics / Q000378:metabolism*; D027805:Phaseolus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D018517:Plant Roots; D018520:Plant Shoots; D012965:Sodium Chloride / Q000494:pharmacology*
D012965:Sodium Chloride; D042966:Cytochrome-B(5) Reductase; D009251:NADPH-Ferrihemoprotein Reductase