The stability assessment of the morphological and functional characteristics of rhizospheric strains of Bacillus subtilis using atomic force microscopy
Section: Methodology and research methods. Models and forecasts
The important advantage of atomic force microscopy (AFM) is the low power requirements for the studied objects, which allows studying living cells without fixation and with high resolution. It was proposed to use AFM to determine the morphometric and elastic-mechanical characteristics of the marker specie Bacillus subtilis isolated from the rhizosphere of the Cucurbita pepo L. crop in different vegetative phase of plant development. These characteristics of the microorganism are indicators of their functional activity and resistance to the action of biotic and abiotic environmental factors. It was shown that some parameters (length, width and height, elastic modulus, and the root mean square roughness) of B. subtilis isolated at different phases of plant growth were stable. So, elastic modulus of the bacilli was equal to 5.9 ± 0.2 MPa in plant sprouting phase, 5.8 ± 0.1 MPa in the phase of budding, 6.0 ± 0.3 MPa in the phase of flowering 5.7 ± 0.3 MPa in the phase of fruiting of the plant. The indicator of the root mean square surface roughness was equal to 37.5 ± 0.6 nm in plant sprouting phase; 35.1 ± 4.6 nm in the phase of budding; 31.8 ± 2.8 nm in the phase of flowering and 40.0 ± 2.1 nm in the phase of fruiting of the plant. AFM study of the surface of B. subtilis cells revealed a change of the adhesion force of the studied strains. This indicator was equal to 32.0 ± 6.0 nN and 41.0 ± 8.0 nN in plant sprouting and budding phases respectively. And the adhesion force was increasing significantly in the flowering and fruiting phase in comparison to the first phases (73.0 ± 5.0 nN and 69.0 ± 3.0 nN, respectively; p <0.05).
The use of atomic force microscopy technology has shown its effectiveness in studying of the stability of the morphometric and elastic-mechanical characteristics of B. subtilis, which are indicators of functional activity of the plant. It was suggested an approach to the development of a methodology for assessing and managing the quality of ecosystem components based on the use of a new information method for the study of marker biological objects.
Keywords: Bacillus subtilis, rhizospheric bacteria, bacterial-plant symbiosis, atomic force microscopy, morpho-functional properties of bacteria
ISSN 1995-4301
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