FTIR spectroscopic studies of bacterial cellular responses to environmental factors, plant-bacterial interactions and signalling

Modern spectroscopic techniques are highly useful in studying diverse processes in microbial cells related to or incited by environmental factors. Spectroscopic data for whole cells, supramolecular structures or isolated cellular constituents can reflect structural and/or compositional changes occurring in the course of cellular metabolic responses to the effects of pollutants, environmental conditions (stress factors); nutrients, signalling molecules (communication factors), etc. This information on the molecular level, often obtained using non-destructive techniques with minimal sample preparation, is of importance for basic studies on mechanisms of bacterial tolerance to stresses and their impact on bacterial metabolism, as well as for applied multidisciplinary research in the fields related to biotechnology, bioremediation, agriculture, biogeochemistry, etc. In the present communication, some recent examples are reviewed and discussed which illustrate the applicability of Fourier transform infrared (FTIR) spectroscopy for monitoring metabolic changes in soil bacteria, using the examples of intensively studied plant-growth-promoting rhizobacteria of the genus Azospirillum . Compositional and structural changes occurring in whole bacterial cells in response to different stress factors and plant signals, as well as spectroscopic images of relevant biospecific interactions are considered from the viewpoint of the possibilities provided by this versatile and easy-to-use technique and its methodology.