Rapid variations in the content of the RNA of the small subunit of ribulose-1,5-bisphosphate carboxylase of mature tobacco leaves in response to localized changes in light quantity. Relationships between the activity and quantity of the enzyme

• Published in: Planta 1988-12, Vol.174 (4), p.488-494
• Main Authors: Prioul, J.-L. (Paris Sud Univ., Orsay (France). Structure et Metabolisme de Plantes), Reyss, A
• Format: Article
• Language: English
• Subjects: AGE; ARN MENSAJERO; ARN MESSAGER; Biological and medical sciences; Blattalter; Chloroplasts; EDAD; ENZIMAS; Enzymaktivitaet; ENZYME; ENZYMES; FEUILLE; Fundamental and applied biological sciences. Psychology; Gene expression regulation; HOJAS; Irradiance; LEAVES; Licht; LIGHT REGIMES; MESSENGER RNA; Metabolism; mRNS; Nicotiana; NICOTIANA TABACUM; Peas; Photoperiod; Plant physiology and development; Plants; REGIME LUMINEUX; REGIMENES DE LUZ; RNA
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/BF00634477

Mature green leaves from tobacco (Nicotiana tabacum L.) plants were submitted to contrasting light conditions; half of each leaf was shaded (changed from 60 to 25 μmol photons·m-2·s-1 = LL) and the other half was exposed to higher light (changed from 60 to 360 μmol·m-2·s-1 = HL) for 24 h. The activity and quantity of ribulose-1,5-bisphosphate carboxylase (RuBP-Case) were measured during the first 24 h in each leaf region and the variation was compared with that of small subunit (SSU)- and large subunit (LSU)-mRNA contents determined by a hybridot technique. Each leaf half responded separately to the actual light received. The activity of RuBPCase increased progressively in the HL zones and decreased in the LL zones. The RuBPCase-protein content was not significantly modified during the first 24 h but SSU-mRNA content responded very rapidly to the treatment. Within 2 h a significant difference in SSU mRNA appeared between LL and HL zones: at the end of the photoperiod the content in LL zones was approx. 25% of the initial value. The increase in the exposed zone, however, was not significant, indicating that there was a dissymmetry of the response to variation in incident white light. The LSU-mRNA contents from the same leaf extracts were totally unaffected by the light treatment. No day-night variations were noted in either SSU or LSU mRNAs in control plants.