Microbial invasions can compromise ecosystem services and spur dysbiosis and disease in hosts. Nevertheless, the mechanisms determining invasion outcomes often remain unclear. Here, we examine the role of iron-scavenging siderophores in driving invasions of Pseudomonas aeruginosa into resident communities of environmental pseudomonads. Siderophores can be ‘public goods’ by delivering iron to individuals possessing matching receptors; but they can also be ‘public bads’ by withholding iron from competitors lacking these receptors. Accordingly, siderophores should either promote or impede invasion, depending on their effects on invader and resident growth. Using supernatant feeding and invasion assays, we show that invasion success indeed increased when the invader could use its siderophores to inhibit (public bad) rather than stimulate (public good) resident growth. Conversely, invasion success decreased the more the invader was inhibited by the residents’ siderophores. Our findings identify siderophores as a major driver of invasion dynamics in bacterial communities under iron-limited conditions.

中文翻译：

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铁载体通过其作为公益与公益的双重作用推动细菌群落的入侵动态

微生物入侵会损害生态系统服务并刺激宿主的生态失调和疾病。然而，决定入侵结果的机制通常仍不清楚。在这里，我们研究了铁清除铁载体在驱动铜绿假单胞菌入侵中的作用进入环境假单胞菌的居民社区。铁载体可以通过向拥有匹配受体的个体输送铁而成为“公共物品”；但它们也可能是“公共坏事”，因为它们不让缺乏这些受体的竞争对手提供铁。因此，铁载体应该促进或阻止入侵，这取决于它们对入侵者和居民生长的影响。使用上清液喂养和入侵测定，我们表明，当入侵者可以使用其铁载体抑制（公共不良）而不是刺激（公共利益）居民生长时，入侵成功确实增加了。相反，入侵者被居民的铁载体抑制得越多，入侵成功率就越低。我们的研究结果确定铁载体是铁限制条件下细菌群落入侵动态的主要驱动力。