Dependence of the Adaptation of the Strain Glutamicibacter sp. SMB32 to a High Salinity Environment Depending on Growth Stage and Temperature

The pool of compatible solutes of the strain Glutamicibacter sp. SMB32, phylogenetically closely related to the species Glutamicibacter halophytocola, was studied under high salinity conditions depending on the growth phase and temperature. In cells at the exponential growth phase, the intracellular amount of glutamate increased with an increase in the salinity of the medium to 5% NaCl, but it had an inverse relationship with the osmolarity of the cultivation medium at 8 and 10% NaCl. The pool of trehalose in the cells of the strain SMB32 increased with an increase in the salinity of the medium to 5% NaCl, but its intracellular amount did not change significantly in the presence of 8 and 10% NaCl. A positive correlation between the salinity of the medium and the intracellular amount in Glutamicibacter sp. SMB32 cells was found for proline only. In the cells grown to the stationary growth phase in a medium containing 5 and 10% NaCl, proline was not detected. At the same time, the content of trehalose in the cells increased. In this work, the effect of the combined action of abiotic factors on the synthesis of secondary metabolites by cells of bacteria of the genus Glutamicibacter was studied for the first time. It was shown that the simultaneous action of high osmotic pressure (5% NaCl) and elevated temperature (32°C) leads to an additive effect with respect to the compound, the synthesis of which they affect separately. Thus, in the cells of the SMB32 strain, a multiple increase in the synthesis of trehalose was noted, which is involved in the adaptation of cells both to the increased osmotic pressure of the medium and to the effect of high temperature. While the simultaneous action of abiotic factors did not affect the amount of proline in the cells. These observations revealed that trehalose is critical for growth at high temperatures, while the leading role belongs to proline in the adaptation of the strain Glutamicibacter sp. SMB32 to high salt concentrations. The obtained data can be used for the development of methods for controlling the metabolic state of autochthonous bacteria of the genus Glutamicibacter by introducing solutions of compatible solutes with their ratio, selected taking into account the current abiotic factors.