Genetic stability of Lactiplantibacillus plantarum P-8 during continuous subculturing

Abstract:

[Background] Lactiplantibacillus plantarum P-8 is a lactic acid bacterium with excellent prebiotic properties. Exploring its genetic stability during short-term continuous subculturing helps to evaluate the stability of the cells in production. [Objective] To study the genetic stability of L. plantarum P-8 subcultured in MRS medium at 37 ℃ for 100 generations. [Methods] We observed the cell morphology and measured the carbohydrate utilization ability of L. plantarum P-8 subcultured for 0, 25, 50, 75, and 100 generations in MRS medium at 37 ℃. The whole genomes of cells subcultured for different generations were sequenced by the second- and third-generation sequencing. Comparative genomics was employed to comprehensively analyze the genetic stability of the cells during the 100 generations. [Results] The cell morphology and carbohydrate utilization ability of L. plantarum P-8 showed no significant changes during continuous subculturing for 100 generations. With the genome of the original cells as a reference, the genomic stability of different generations was compared. The cells of all the generations had single nucleotide polymorphism (SNP) sites, while the number of SNP sites was <21. The genomes of the cells at different generations had good collinearity and high similarity. The results of carbohydrate activity enzyme annotation showed no significant differences among different generations (P>0.05). [Conclusion] L. plantarum P-8 has good genetic stability during continuous subculturing for 100 generations in MRS medium at 37 ℃. This study laid a genetic foundation for the industrial application of this strain.