Accepted_test

S. maltophilia is a highly heterogeneous species known for its ability to adapt to various environments, The study aimed to investigate the distribution and conservation of antiphage defense systems in five newly isolated S. maltophilia strains from different ecosystems in Novosibirsk, Russia, and compare them with other available S. maltophilia strains in the NCBI GenBank.

The results showed that the five locally sequenced S. maltophilia strains shared 65% of their genes, compared to 4% shared among most strains in the pangenome matrix. Only 8% of the studied strains had complete CRISPR/Cas systems, which is lower than the general distribution in bacteria (42%). A total of 72 different anti-phage systems and subsystems were identified, with the anti ssDNA phages Wadjet I system, restriction modification systems, Gabija system with endonuclease activity, and the abortive infection system AbiE 4 being the most common. The distribution of these systems did not follow a trend related to the site of isolation of the strains or their evolutionary history, suggesting that the acquisition of these systems is linked to the presence of phages and other bacterial strains in the microecosystems. Most of the widely distributed systems were highly variable, except for Wadjet I and AbiE, which were conserved, the essential JetD gene of the topoisomerase IV activity was absent from half Wadjet I systems, suggesting that those systems are inactive .