Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 20, 2006
Publication Date: May 7, 2007
Citation: Martin, P.A., Gundersen, D.E., Blackburn, M.B., Buyer, J.S. 2007. Chromobacterium suttsuga sp. nov., bacteria that kill colorado potato beetle and other pest insects.. International Journal of Systematic and Evolutionary Microbiology 57:993-999.
Insects become resistant to both chemical and biological means of pest control. Therefore, scientists must continue to search for new compounds and /or organisms to replace those to which the insects become resistant. We have discovered a purple bacterium that make toxins that kill Colorado potato beetles, which are resistant to most pesticides, as well as corn rootworms and diamond back moths. This purple bacterium is different from any bacterial species that have been described. It is similar to Chromobacterium violaceum in that it produces a purple pigment, but is different enough to be considered a separate species. It has a different sequence in its ribosomal DNA and a different structure of fatty acids in its cell wall from other described species of similar bacteria. It also grows at lower temperatures. Because it was found under a hemlock tree, Tsuga canadensis, we have named the new species Chromobacterium suttsuga. A description of this new species of bacteria can be used by scientists in comparative studies that examine insect versus mammalian toxins and similarities to non-toxic bacteria. The bacterial strain itself shows promise for controlling a variety of pest insects.
Strain PRAA4-1T, a Gram-negative purple bacterium, was isolated from forest soil and found to be toxic to Colorado potato beetle larvae and other insects. The cells were rods 0.67 " 0.007 Fm wide and 2.43 " 0.05 Fm long. The temperature range for growth was 10-40E C, the optimum being between 25 and 28EC . The range of pH for growth was 5.0-9.0, with the optimum range pH 6.5-8.0. The G+C content DNA was 64.5 mol %. On the basis of phenotypic, genotypic, and phylogenetic analyses, strain PRAA4-1T is proposed as the type strain of a new species of the genus Chromobacterium, Chromobacterium suttsuga sp. nov. (= NRRL B30655 ).