Leaf Catalase mRNA and Catalase-Protein Levels in a High-Catalase Tobacco Mutant with O₂-Resistant Photosynthesis

• Published in: Plant physiology (Bethesda) Vol. 97; no. 4; pp. 1592 - 1595
• Main Authors: Zelitch, Israel, Evelyn A. Havir, Brian Mc Gonigle, McHale, Neil A., Nelson, Timothy
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-12-1991
• Subjects: Biological and medical sciences; CDNA libraries; Communications; Complementary DNA; Electrophoresis; Fundamental and applied biological sciences. Psychology; Gels; Leaf area; Leaves; Messenger RNA; Metabolism; Photosynthesis; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plants; RNA; Enzyme; Gene expression; Nicotiana tabacum; Subunit; Ribulosebisphosphate carboxylase; Enzymatic activity; Catalase; Dicotyledones; Angiospermae; Spermatophyta; Solanaceae; Kinetics; Photosynthesis
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.97.4.1592

Experiments were conducted with a tobacco (Nicotiana tabacum) mutant with 40 to 50% greater catalase activity than wild type that is associated with a novel form of O2-resistant photosynthesis. The apparent Km for H2O2 was the same in mutant and wild-type leaf extracts. Tobacco RNAs were hybridized with Nicotiana sylvestris catalase cDNA, and a threefold greater steady-state level of catalase mRNA was found in mutant leaves. Steady-state levels of ribulose-1, 5-bisphosphate carboxylase small subunit mRNA were similar in mutant and wild type. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of partially purified catalase showed that the protein concentration in the band corresponding to catalase was higher in the mutant than in the wild type. Separation of leaf catalase proteins by isoelectric focusing revealed the presence of five major bands and one minor band of activity. The distribution of the catalase activity among these forms was similar in mutant and wild type, although the total activity was higher in the mutant in all five major bands. The results indicate that the enhanced catalase activity in mutant leaves is caused by an increase in synthesis of catalase protein and that this trait is mediated at the nucleic acid level.