Specific detection of form IA RubisCO genes in chemoautotrophic bacteria

The analysis of RubisCO genes is a highly useful instrument to explore the diversity of chemoautotrophic bacteria using the Calvin–Benson–Bassham cycle for CO(2) fixation. However, because of the wide taxonomic distribution of phylogenetically related RubisCO forms, environmental studies targeting chemoautotrophs are hampered in habitats dominated by phototrophs. Here, we report the development of a gene marker that specifically detects form IA RubisCO genes in bacteria, excluding photoautotrophic representatives. The high specificity of the PCR assay was confirmed by sequence analysis of DNA obtained from the photic zone of six lakes, were chemoautotrophs are outnumbered by Cyanobacteria also using form IA RubisCO for CO(2) assimilation.