Abstract
In the glucose-tolerant strain of Synechocystis sp. PCC 6803, we found two types of cells with distinct growth properties. Under photoautotrophic conditions at any light intensity, one type gave larger colonies (designated WL) than the other (designated WS). Notably, the WL cells produced much larger colonies than the WS cells at higher light intensity. In contrast, growth of the WL cells was severely suppressed under mixotrophic conditions with glucose and light, while the WS cells grew normally. A gene which could complement the WL phenotype was obtained from a wild-type genomic library. The gene, designated pmgA, coded for a 23 kDa polypeptide of 204 amino acid residues with no apparent homology to known genes. In the WL genome, the base substitution of T for C at position 193 of pmgA caused replacement of Leu with Phe at position 65 of the product. The phenotype of pmgA disruption mutants was similar to that of the WL cells, indicating that the WS cells expressed a functional pmgA product. By direct sequencing of polymerase chain reaction-amplified pmgA from genomic DNA, it was revealed as an example of microevolution that WL had expelled WS from the photoautotrophic culture of wild-type in our laboratory for a year or so. Mixed culture in liquid also demonstrated that the WL cells increased gradually under photoautotrophic conditions, while they decreased rapidly under photomixotrophic conditions. These results suggest that pmgA product is essential for photomixotrophic growth, whereas it represses photoautotrophic growth. To our knowledge, the WL cells and pmgA-disrupted mutants are the first in cyanobacteria, which shows much improved photosynthetic growth than wild-type especially at high light intensity.
Similar content being viewed by others
References
Altschul SF, Gish W, Miller W, Myers EW and Lipman DJ (1990) Basic local alignment search tool. J Mol Biol 215: 403-410
Beuf L, Bèdu S, Durand MC and Joset F (1994) A protein involved in co-ordinated regulation of inorganic carbon and glucose metabolism in the facultative photoautotrophic cyanobacterium Synechocystissp. PCC6803. Plant Mol Biol 25: 855-864
Chow TYK, Perkins EL and Resnick MA (1992) Yeast RNC1 encodes a chimeric protein, RhoNUC, with a human rho motif and deoxyribonuclease activity. Nucleic Acids Res 20: 5215-5221
Collier JL and Grossman AR (1994) A small polypeptide triggers complete degradation of light-harvesting phycobiliproteins in nutrient-deprived cyanobacteria. EMBO J 13: 1039-1047
Dzelzkalns VA and Bogorad L (1988) Molecular analysis of a mutant defective in photosynthetic oxygen evolution and isolation of a complementing clone by a novel screening procedure. EMBO J 7: 333-338
Gustafsson C, Lindstroem PHR, Hagervall TG and Esberg KB (1991) The trmApromoter has regulatory features and sequence elements in common with the ribosomal RNA P1 promoter family of Escherichia coli. J Bacteriol 173: 1757-1764
Kaneko T, Sato S, Kotani H, Tanaka A, Asamizu E, Nakamura Y, Miyajima N, Hirosawa M, Sugiura M, Sasamoto S, Kimura T, Hosouchi T, Matsuno A, Muraki A, Nakazaki N, Naruo K, Okumura S, Shimpo S, Takeuchi C, Wada T, Watanabe A, Yamada M, Yasuda M and Tabata S (1996) Sequence analysis of the genome of the unicellular cyanobacterium Synechocystissp. strain PCC 6803. II. Sequence determination of the entire genome and assignment of potential protein-coding regions. DNA Res 3: 109-136
Krupa Z, Öquist G and Gustafsson P (1991) Photoinhibition of photosynthesis and growth responses at different light levels in psbAgene mutants of the cyanobacterium Synechococcus. Physiol Plant 82: 1-8
Mäenpää P, Kallio T, Mulo P, Salih G, Aro EM, Tyystjärvi E and Jansson C (1993) Site-specific mutations in the D1 polypeptide affect the susceptibility of Synechocystis6803 cells to photoinhibition. Plant Mol Biol 22: 1-12
Narusaka Y, Murakami A, Saeki M, Kobayashi H and Satoh K (1996) Preliminary characterization of a photo-tolerant mutant of Synechocystissp. PCC6803 obtained by in vitro random mutagenesis of psbA2. Plant Sci 115: 261-266
Pelroy RA, Rippka R, Stanier RY (1972) Metabolism of glucose by unicellular blue-green algae. Arch Microbiol 87: 303-322
Rippka R, Deruelles J, Waterbury JB, Herdman M and Stanier RY (1979) Generic assignments, strain histories and properties of pure cultures of cyanobacteria. J Gen Microbiol 111: 1-61
Stanier RY, Kunisawa R, Mandel M and Cohen-Bazire G (1971) Purification and properties of unicellular blue-green alga (order Chroococcales). Bacteriol Rev 35: 171-205
Williams JGK (1988) Construction of specific mutations in Photosystem II photosynthetic reaction center by genetic engineering methods in Synechocystis6803. Methods Enzymol 167: 766-778
Yokoyama E, Murakami A, Sakurai H and Fujita Y (1991) Effect of supra-high irradiation on the photosynthetic system of the cyanophyte SynechocystisPCC6714. Plant Cell Physiol 32: 827-834
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hihara, Y., Ikeuchi, M. Mutation in a novel gene required for photomixotrophic growth leads to enhanced photoautotrophic growth of Synechocystis sp. PCC 6803. Photosynthesis Research 53, 243–252 (1997). https://doi.org/10.1023/A:1005879905365
Issue Date:
DOI: https://doi.org/10.1023/A:1005879905365