Genome Stability of Bacillus velezensis after Two-Year Exposure in Open Space

• Published in: Molecular biology (New York) Vol. 58; no. 1; pp. 33 - 42
• Main Authors: Fialkina, S. V., Deshevaya, E. A., Rakitin, A. L., Orlov, O. I.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-02-2024; Springer Nature B.V
• Subjects: Bacillus velezensis; Biochemistry; Biomedical and Life Sciences; Comparative analysis; Environmental conditions; Genomes; Genomics. Transcriptomics; Human Genetics; Life Sciences; Missense mutation; Single-nucleotide polymorphism; Spore-forming bacteria; impact of cosmic factors; bacterial spores; “Test” space experiment; low Earth orbit; International Space Station (ISS)
• ISSN: 0026-8933; 1608-3245
• DOI: 10.1134/S0026893324010023

—Spore-forming bacteria have a unique resistance to negative environmental conditions, including aggressive space factors, and are an excellent model for studying adaptation mechanisms and survival strategies at the molecular level. The study analyzed the genome of
Bacillus velezensis
, which remained viable after a 2-year exposure in outer space on the outer surface of the ISS as part of the Test space experiment. A comparative analysis of the draft genomes of the exhibit strain and the ground control did not reveal significant changes; the average nucleotide identity was 99.98%, which indicates the ability of microorganisms to maintain genome stability in space conditions, due to both increased stress resistance of bacterial spores and efficient operation of the system of repair of accumulated changes. The study of a single nucleotide polymorphism in the genome of
B. velezensis
revealed nine point substitutions, three of which are in intergenic regions, six in protein-coding genes, three of them are missense mutations, two nucleotide deletions leading to a shift in the reading frame, and one synonymous substitution. The profiles of the housekeeping genes were determined during MLST typing and it was found that the allelic profiles obtained for
B. velezensis
T15.2 and 924 strains do not correspond to any of the previously described sequence types.The presented results indicate the ability of
B. velezensis
bacteria to maintain the viability of spores and the integrity of the genome for a long time under extreme conditions of outer space, which is important for the problem of planetary protection, as well as the potential possibility of performing biotechnological processes based on
B. velezensis
during space exploration.