摘要
Outer space,characterized by high radiation levels,microgravity,and extreme temperature fluctuations,poses unique challenges to microbial growth and survival.However,the effects of space conditions on beneficial microbes such as probiotics remain poorly explored.In this study,we exposed Lacticaseibacillus paracasei PC-01 to mutagenesis in space,7970 km above Earth,and detected extensive adaptive changes post-mutation.Genomic analysis revealed significantly higher mutation rates in space mutants compared to ground-control strains.Unique single nucleotide polymorphisms(SNPs)were identified in the space mutant HG-1,but were absent in ground-control strains.The modification of DNA methylation in space mutants shifted from 6 mA to 4 mC,with 4 mC motifs only being found in strains HG-12,HG-19,and HG-46.The high-frequency SNPs and methylation motifs were closely linked to genes involved in carbohydrate metabolism.Notably,the space mutants and ground-control strains both lost the genes lacE,lacF_2,and lacG,which are responsible for the transport and decomposition of lactose and were originally present within a plasmid in PC-01.Phenotypic and metabonomic analyses revealed changes in carbohydrate utilization ability in space mutants.In particular,the space mutant HG-12 showed a significant ability to utilize 44 carbon sources.Moreover,although the ability of space mutants and ground-control strains to utilize lactose was greatly reduced,these mutants exhibited different metabolic characteristics and pathway preferences in fermented milk.These findings suggest that the space environment induces comprehensive genetic,methylation,and metabolic remodeling in Lacticaseibacillus paracasei PC-01,enhancing its survival capabilities in space.
基金
Research Fund for the National Natural Science Foundation of China(32325040,32394050)
Inner Mongolia Science&Technology planning project(2023KYPT0019)
the Key Laboratory of Infinite-dimensional Hamiltonian System and Its Al-gorithm Application(Inner Mongolia Normal University),Ministry of Education(2023KFJD01)
the earmarked fund for CARS36.
