Photosynthesis Research

, Volume 70, Issue 1, pp 85–106

An overview of the genome of Nostoc punctiforme, a multicellular, symbiotic cyanobacterium


    • Section of MicrobiologyUniversity of California
  • Jeff Elhai
    • Department of BiologyUniversity of Richmond
  • Teresa Thiel
    • Department of BiologyUniversity of Missouri
  • Malcolm Potts
    • Department of BiochemistryVirginia Polytechnic Institute and State University
  • Frank Larimer
    • Computational BiologyOak Ridge National Laboratory
  • Jane Lamerdin
    • Biology and Biotechnology Research ProgramLawrence Livermore National Laboratory
  • Paul Predki
    • DOE Joint Genome Institute
  • Ronald Atlas
    • Department of BiologyUniversity of Louisville

DOI: 10.1023/A:1013840025518

Cite this article as:
Meeks, J.C., Elhai, J., Thiel, T. et al. Photosynthesis Research (2001) 70: 85. doi:10.1023/A:1013840025518


Nostoc punctiforme is a filamentous cyanobacterium with extensive phenotypic characteristics and a relatively large genome, approaching 10 Mb. The phenotypic characteristics include a photoautotrophic, diazotrophic mode of growth, but N. punctiforme is also facultatively heterotrophic; its vegetative cells have multiple developmental alternatives, including terminal differentiation into nitrogen-fixing heterocysts and transient differentiation into spore-like akinetes or motile filaments called hormogonia; and N. punctiforme has broad symbiotic competence with fungi and terrestrial plants, including bryophytes, gymnosperms and an angiosperm. The shotgun-sequencing phase of the N. punctiforme strain ATCC 29133 genome has been completed by the Joint Genome Institute. Annotation of an 8.9 Mb database yielded 7432 open reading frames, 45% of which encode proteins with known or probable known function and 29% of which are unique to N. punctiforme. Comparative analysis of the sequence indicates a genome that is highly plastic and in a state of flux, with numerous insertion sequences and multilocus repeats, as well as genes encoding transposases and DNA modification enzymes. The sequence also reveals the presence of genes encoding putative proteins that collectively define almost all characteristics of cyanobacteria as a group. N. punctiforme has an extensive potential to sense and respond to environmental signals as reflected by the presence of more than 400 genes encoding sensor protein kinases, response regulators and other transcriptional factors. The signal transduction systems and any of the large number of unique genes may play essential roles in the cell differentiation and symbiotic interaction properties of N. punctiforme.

cellular differentiationcyanobacteriumgenome analysisnitrogen fixationNostoc punctiformeoxygenic photosynthesissymbiosis

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© Kluwer Academic Publishers 2001