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PHYLOGENETIC PLACEMENT, GENOME SIZE, AND GC CONTENT OF THE LIQUID-HYDROCARBON-PRODUCING GREEN MICROALGA BOTRYOCOCCUS BRAUNII STRAIN BERKELEY (SHOWA) (CHLOROPHYTA)1

Authors

  • Taylor L. Weiss,

    1. Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
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  • J. Spencer Johnston,

    1. Department of Entomology, Texas A&M University, College Station, Texas 77843-2475, USA
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  • Kazuhiro Fujisawa,

    1. Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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    • 2

      Present address: Bristol-Myers Squibb, Shinjuku i-Land Tower 5-, Nishi-Shinjuku-6, Shinjuku, Tokyo 163-1328, Japan.

  • Koremitsu Sumimoto,

    1. Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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  • Shigeru Okada,

    1. Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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  • Joe Chappell,

    1. Department of Plant & Soil Sciences, Plant Biology Program, University of Kentucky, Lexington, Kentucky 40546, USA
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  • Timothy P. Devarenne

    1. Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
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  • 1

    Received 10 April 2009. Accepted 7 December 2009.

Abstract

We report the genome size and the GC content, and perform a phylogenetic analysis on Botryococcus braunii Kütz., a green, colony-forming, hydrocarbon-rich alga that is an attractive source for biopetroleum. While the chemistry of the hydrocarbons produced by the B race of B. braunii has been studied for many years, there is a deficiency of information concerning the molecular biology of this alga. In addition, there has been some discrepancy as to the phylogenetic placement of the Berkeley (or Showa) strain of the B race. To clarify its classification, we isolated the Berkeley strain nuclear SSU (18S) rRNA gene and β-actin cDNA and used these sequences for phylogenetic analysis to determine that the Berkeley strain belongs to the Trebouxiophyceae class. This finding is in agreement with other B races of B. braunii, indicating the Berkeley strain is a true B race of B. braunii. To better understand molecular aspects of B. braunii, we obtained the Berkeley strain genome size as a first step in genome sequencing. Using flow cytometry, we determined the B. braunii Berkeley genome size to be 166.2 ± 2.2 Mb. We also estimated the GC content of the Berkeley strain as 54.4 ± 1.2% for expressed gene sequences.

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