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ENUMERATION, ISOLATION, AND CHARACTERIZATION OF ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS (POSTER SESSION)
Citation:
Trinkwalter, T., K. Kusel, R D. Devereux, AND H. L. Drake. ENUMERATION, ISOLATION, AND CHARACTERIZATION OF ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS (POSTER SESSION). Presented at Verein. Allgem. Angewand. Mickrobiol. (VAAM), Munich, Germany, 12-16 March 2000.
Description:
Seagrasses are rooted in anoxic, sulfate-reducing sediments. However, the seagrass root is oxygenated during the daytime, becoming anoxic at night. Root thin sections hydridized with 33P-labeled probes revealed the presence of acetogenic and sulfate-reducing bacteria in the rhizoplane and deep cortex cells [1]. MPN analyses demonstrated that H2-utilizing acetogens were enriched in the seagrass root and rhizosphere sediment compared to unvegetated sediment. In contrast, sulfate reducers, which dominated the anaerobic microflora, were not enriched in the root and rhizosphere sediment. An H2-utilizing acetogen was isolated from the highest growth-positive MPN dilution of the seagrass root and characterized. Its 16S rRNA gene sequence was closely related to that of Clostridium glycolicum (99.7%), which is not known to be an acetogen. These results indicate that the biogeochemistry of this sulfate-reducing habitat promotes the colonization of the rhizosphere by acetogens.