2025-11-03 マックス・プランク研究所
<関連情報>
- https://www.mpg.de/25646980/bacteria-borrow-viruses-to-spread-their-own-defences
- https://www.pnas.org/doi/10.1073/pnas.2512465122
ジャンボファージを介したゲノムアイランドの導入 Jumbo phage–mediated transduction of genomic islands
Yansong Zhao, Yue Ma, Christina Vasileiou, +2 , and Paul B. Rainey
Proceedings of the National Academy of Sciences Published:October 28, 2025
DOI:https://doi.org/10.1073/pnas.2512465122
Significance
The environmental mobilome largely remains an underexplored reservoir of mobile genetic elements (MGEs), partly due to its complexity that hinders mechanistic studies. Here, we report a real-time experiment in which a single strain cultured with sterile filtrate from a complex microbial community captured genetic elements carrying diverse, previously uncharacterized gene cargos. We show that a jumbo bacteriophage mediates intercellular transfer of one of the elements providing evidence that jumbo phages can harbor genomic parasites. The elements represent a widespread class of mobile DNA dependent on a tyrosine integrase targeting a conserved genomic site. Our findings reveal insights into the hidden diversity and dynamics of MGEs and their interactions in natural environments.
Abstract
Bacteria acquire new genes by horizontal gene transfer, typically mediated by mobile genetic elements (MGEs). While plasmids, bacteriophages, and certain integrative and conjugative elements are well characterized, the broader diversity of MGEs remains poorly understood. Here, we cultured the bacterium Pseudomonas fluorescens SBW25 with sterile filtrate obtained from garden compost communities. Genome sequencing of derived colonies revealed acquisition of three different mobile elements, each integrated immediately downstream of tmRNA, each flanked by direct repeats, and each encoding a tyrosine integrase (intY) plus putative phage defense systems. Absent are genes with recognized roles in autonomous transfer. Interrogation of DNA sequence databases showed that similar elements are widespread in the genus Pseudomonas and beyond, with Vibrio Pathogenicity Island-1 from Vibrio cholerae as a notable example. Bioinformatic analyses reveal evidence of extensive horizontal transfer among diverse hosts. Detailed analysis of a single element, I55, showed that it is transferred between cells by jumbo phages, and confers fitness benefits via a type II restriction-modification system.
