Effects of Aqua-Glycerol Uptake Facilitator Protein GlpF on Spore Germination of Bacillus subtilis

Killing spores is an important challenge for the development of the food industry. After germination, the resistance of spores disappears and they are more easily killed, which is currently the main strategy for their destruction. Therefore, study of the mechanism of spore germination is of great significance for improving methods of spore inactivation. Previous studies have shown that the hydration of the spore core region, accompanied by the disappearance of bacterial spore resistance, is a key step in the germination pathway of bacterial spores. However, the specific mechanism of this process has been studied very little. In this study, <i>Bacillus subtilis</i> PY79 was used as a model strain, and its single water glycerol channel protein (GlpF) was regarded as a starting point to explore the mechanism of water transport during spore germination. First, we constructed <i>glpF</i> mutants and overexpression strains and discovered that the deletion of <i>glpF</i> did not affect the growth of bacterial vegetative cells and spores. Further germination experiments on the spores of the <i>glpF</i>-deficient strain through detecting calcium dipicolinate and absorbance of spores showed that the germination rate of the mutant strain spores increased, while increasing the water activity did not affect the results caused by <i>glpF</i> deletion. Meanwhile, overexpressed <i>glpF</i> affected the permeability of the spore coat. Finally, when treating spores with ultra-high pressure, the spores lacking <i>glpF</i> were more likely to be inactivated. The above results have suggested that the <i>glpF</i> gene plays an important role in spore germination.