Characterization of rbcS genes in the fern Pteris vittata and their photoregulation

• Published in: Planta Vol. 206; no. 2; pp. 204 - 214
• Main Authors: Eilenberg, H, Hanania, U, Stein, H, Zilberstein, A
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01.10.1998; Springer
• Subjects: Amino Acid Sequence; amino acid sequences; Base Sequence; Biological and medical sciences; blue light; carbon dioxide; Cloning, Molecular; Complementary DNA; DNA, Complementary; efficiency; Ferns; Fundamental and applied biological sciences. Psychology; Gametophytes; genbank/x73136; genbank/x77813; genbank/x98412; genbank/x98413; genbank/x98414; gene expression; Gene Expression Regulation, Enzymologic - radiation effects; Gene Expression Regulation, Plant - radiation effects; Genes; genetic regulation; Genomics; Introns; Light; Messenger RNA; Metabolism; Molecular Sequence Data; Multigene Family; nucleotide sequences; photosynthesis; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plants; Plants - genetics; Polymerase chain reaction; promoter regions; Pteris; red light; ribulose-bisphosphate carboxylase; Ribulose-Bisphosphate Carboxylase - genetics; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; Sequence Homology, Amino Acid; Enzyme; Red light; Ribulose-bisphosphate carboxylase; Homology; Lyases; Pteridophyta; Subunit; Carbon-carbon lyases; Complementary DNA; Carboxy-lyases; Gametophyte; Development; Multigene family; Regulatory sequence; Chemical composition; Blue light; Photosynthesis; Sequencing; Photoregulation; Filicineae
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s004250050392

The fern Pteris vittata L. belongs to the evolutionarily highest group of vascular plants that still maintains a free-living gametophytic stage. The two-dimensional gametophytes developed under blue light exhibit higher CO2 fixation efficiency and different ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) small subunit (SSU) composition when compared to the red-induced filamentous gametophytes (H. Eilenberg et al., 1991, Plant Physiol 95: 298-304). To unravel the correlation between SSU structural differences and light regulation, two rbcS genes and two additional partial cDNAs were characterized. Fern rbcS genes resemble those of higher plants in their promoter light-regulatory elements (LREs) and intron number and positions. However, the primary structure of the fern mature SSUs displays much higher divergency within the gene family. This structural variability was correlated with differential steady-state mRNA levels under red and blue light. Genes rbcS-1 and -4 show 4- to 6-fold higher transcript levels in red light while rbcS-2 and -3 contribute relatively more to the blue rbcS mRNA levels. Five of the 12 amino acids that differ between rbcS-2 and -4 affect hydrophobicity and might play a crucial role in determining the efficiency of CO2 fixation. Dendrograms of Rubisco SSUs and LSUs indicate early divergence of the fern types from the rest of the vascular plants. However, prominent higher-plant-like Rubisco features such as high carboxylation efficiency, promoter LREs and exon-intron structure, suggest that molecular specialization of the higher-plant Rubisco prototype occurred earlier than the emergence of ferns.