Multi-omics analysis of Bacillus. subtilis spores formed at different environmental temperatures reveal differences at the morphological and molecular level.

Spore-forming bacteria play an essential role in the food industry and public health. Through sporulation, bacteria can withstand extreme environmental conditions that vegetative cells cannot survive. Although it is well established that the same environmental factors that affect the growth of vegetative cells also profoundly influence sporulation, the mechanisms of how growth conditions affect spore structure and function remain unknown. Prior research has shown that spores prepared at higher temperatures are more heat resistant than those prepared at lower temperatures. The present study examines, both at metabolomic and proteomic levels, the effect of different sporulation temperatures (25, 37 and 42{degrees}C) on the small molecule and protein composition of spores (strain PY79) of the model organism B. subtilis. Through differential harvesting times, spores of the same developmental stage were obtained for each temperature regime. The heat resistance, dipicolinic acid content, germination kinetics and spore morphology were assayed to compare spore properties. Metabolome and proteome analysis yielded unparalleled broad molecular detail of the spores formed at different environmental temperatures. Our findings indicate that peptidoglycan biosynthesis and 28 outer-layer proteins play a crucial role in the functional diversity of spores produced by B. subtilis under varying temperatures.