Deep-Sea Lysinibacillus fusiformis sp. 1069 Genome Reveals 3-indoleacetic acid Biosynthesis and Anti-Helicobacter pylori Traits

The extreme conditions in the deep-sea contribute to the complex physiological, biochemical, and molecular biological characteristics of microorganisms. These microorganisms are valuable assets for enzyme discovery and drug development. In this study, a strain of Lysinibacillus fusiformis sp. 1069 was successfully isolated from the deep-sea sediments in the South China Sea. Unexpectedly, the strain was found to synthesize 3-indole acetic acid (IAA). Whole-genome analysis showed that the G+C content was 38.41 mol%, and the total length of the genome was 4,673,526 bp, containing 4,645 coding genes, 84 tRNAs, 17 rRNAs, 13 genomic islands and 3 prophages. According to the genome annotation results, L. fusiformis sp.1069 encodes a complete pathway for synthesizing IAA, which consists of metal thiol transferase (gene1799) and heptadecanylglycerol phosphate synthase (gene3105). In addition, the strain may also have multiple IAA synthesis pathways. The study found that IAA has a significant inhibitory effect on Helicobacter pylori , so we studied the anti- H. pylori ability of IAA. When the IAA concentration reaches 10 mg/mL, the inhibition rate of urease reaches the maximum. Given the critical role of IAA in plant growth and development, these findings enhance our understanding of the diversity and metabolic potential of deep-sea microbials and show promising applications in agriculture and biotechnology.