Membrane lipid integrity relies on a threshold of ATP production rate in potato cell cultures submitted to anoxia

• Published in: Plant physiology (Bethesda) Vol. 120; no. 1; pp. 293 - 300
• Main Authors: Rawyler, A, Pavelic, D, Gianinazzi, C, Oberson, J, Braendle, R
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.05.1999; American Society of Plant Biologists
• Subjects: adenosine triphosphate; Agronomy. Soil science and plant productions; anaerobic conditions; Anoxia; Azides; Biological and medical sciences; biomass; biosynthesis; cell membranes; chemical constituents of plants; cultured cells; Economic plant physiology; energy; energy content; Energy metabolism; Environmental and Stress Physiology; Fatty acids; fermentation; Fundamental and applied biological sciences. Psychology; Hydrolysis; hypoxia; Lipids; Membrane lipids; Metabolism; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); Nonesterified fatty acids; Nutrition. Photosynthesis. Respiration. Metabolism; Phospholipids; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plants; Solanum tuberosum; Cell culture; Energy metabolism; Anoxia; Solanum tuberosum; Structure integrity; Lipids; Autolysis; Dicotyledones; Angiospermae; Plasma membrane; Spermatophyta; Chemical composition; Tuber plant; Solanaceae; ATP
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.120.1.293

In this paper we report on our study of the changes in biomass, lipid composition, and fermentation end products, as well as in the ATP level and synthesis rate in cultivated potato (Solanum tuberosum) cells submitted to anoxia stress. During the first phase of about 12 h, cells coped with the reduced energy supply brought about by fermentation and their membrane lipids remained intact. The second phase (12-24 h), during which the energy supply dropped down to 1% to 2% of its maximal theoretical normoxic value, was characterized by an extensive hydrolysis of membrane lipids to free fatty acids. This autolytic process was ascribed to the activation of a lipolytic acyl hydrolase. Cells were also treated under normoxia with inhibitors known to interfere with energy metabolism. Carbonyl-cyanide-4-trifluoromethoxyphenylhydrazone did not induce lipid hydrolysis, which was also the case when sodium azide or salicylhydroxamic acid were fed separately. However, the simultaneous use of sodium azide plus salicylhydroxamic acid or 2-deoxy-D-glucose plus iodoacetate with normoxic cells promoted a lipid hydrolysis pattern similar to that seen in anoxic cells. Therefore, a threshold exists in the rate of ATP synthesis (approximately 10 micromole g-1 fresh weight h-1), below which the integrity of the membranes in anoxic potato cells cannot be preserved.