Concerted circadian oscillations in transcript levels of nineteen Lha/b (cab) genes in Lycopersicon esculentum (tomato).

Steady-state mRNA levels of nineteen members of the Lha/b (cab) gene family of Lycopersicon esculentum, encoding nine different types of light-harvesting complex (LHC) polypeptides, were determined by primer extension analysis. Each Lha/b gene is expressed and individual mRNAs accumulate to distinct levels. The relative contribution of each Lha/b mRNA to the total Lha/b mRNA levels is very similar in different green organs (leaves, stems, fruits, sepals) and after light treatment of etiolated seedlings. Detailed analysis of Lha/b mRNA accumulation in leaves under light/dark conditions, continuous darkness and continuous light revealed diurnal and circadian oscillations of Lha/b mRNAs for all genes. Only minor instances of divergence from a general expression pattern are apparent. Together these results indicate a concerted expression of all genes, suggesting that similar or identical molecular mechanisms and signal transduction chain control the expression of all Lha/b genes.