Bacterial predators are decisive organisms that shape microbial ecosystems. In this study, we investigated the role of iron and siderophores during the predatory interaction between two rhizosphere bacteria: Myxococcus xanthus, an epibiotic predator, and Sinorhizobium meliloti, a bacterium that establishes nitrogen-fixing symbiosis with legumes. The results show that iron enhances the motility of the predator and facilitates its predatory capability, and that intoxication by iron is not used by the predator to prey, although oxidative stress increases in both bacteria during predation. However, competition for iron plays an important role in the outcome of predatory interactions. Using combinations of predator and prey mutants (non-producers and overproducers of siderophores), we have investigated the importance of competition for iron in predation. The results demonstrate that the competitor that, via the production of siderophores, obtains sufficient iron for growth and depletes metal availability for the opponent will prevail in the interaction. Consequently, iron fluctuations in soils may modify the composition of microbial communities by altering the activity of myxobacterial predators. In addition, siderophore overproduction during predation can alter soil properties, affecting the productivity and sustainability of agricultural operations.

中文翻译：

---

铁载体和铁竞争控制粘细菌捕食动态

细菌捕食者是塑造微生物生态系统的决定性生物体。在这项研究中，我们研究了铁和铁载体在两种根际细菌之间捕食相互作用中的作用：黄粘球菌（一种益生捕食者）和中华根瘤菌（一种与豆科植物建立固氮共生的细菌）。结果表明，铁增强了捕食者的运动性并促进其捕食能力，并且捕食者不会利用铁中毒来捕食，尽管两种细菌在捕食过程中氧化应激都会增加。然而，对铁的竞争在掠夺性相互作用的结果中起着重要作用。利用捕食者和被捕食者突变体（铁载体的非生产者和过量生产者）的组合，我们研究了捕食中铁竞争的重要性。结果表明，通过产生铁载体获得足够的铁用于生长并耗尽对手的金属可用性的竞争者将在相互作用中获胜。因此，土壤中铁的波动可能通过改变粘细菌捕食者的活动来改变微生物群落的组成。此外，捕食过程中铁载体的过量生产会改变土壤特性，影响农业生产的生产力和可持续性。