Explaining how cooperation can persist in the presence of cheaters, exploiting the cooperative acts, is a challenge for evolutionary biology. Microbial systems have proved extremely useful to test evolutionary theory and identify mechanisms maintaining cooperation. One of the most widely studied system is the secretion and sharing of iron‐scavenging siderophores by Pseudomonas bacteria, with many insights gained from this system now being considered as hallmarks of bacterial cooperation. Here, we introduce siderophore secretion by the bacterium Burkholderia cenocepacia H111 as a novel parallel study system, and show that this system behaves differently. For ornibactin, the main siderophore of this species, we discovered a novel mechanism of how cheating can be prevented. Particularly, we found that secreted ornibactin cannot be exploited by ornibactin‐defective mutants because ornibactin receptor and synthesis genes are co‐expressed from the same operon, such that disruptive mutations in synthesis genes compromise receptor availability required for siderophore uptake and cheating. For pyochelin, the secondary siderophore of this species, we found that cheating was possible, but the relative success of cheaters was positive frequency dependent, thus diametrically opposite to the Pseudomonas and other microbial systems. Altogether, our results highlight that expanding our repertoire of microbial study systems leads to new discoveries and suggest that there is an enormous diversity of social interactions out there in nature, and we might have only looked at the tip of the iceberg so far.

中文翻译：

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遗传结构限制了细菌伯克霍尔德氏菌细菌中铁载体合作的利用

解释如何在作弊者面前保持合作，利用合作行为是进化生物学面临的挑战。事实证明，微生物系统对于测试进化论和确定维持合作的机制非常有用。研究最广泛的系统之一是假单胞菌细菌对铁清除铁载体的分泌和共享，现在从该系统获得的许多见解被视为细菌合作的标志。在这里，我们介绍由细菌伯克霍尔德氏菌（Burkholderia cenocepacia）分泌铁载体H111作为一种新颖的并行学习系统，表明该系统的行为有所不同。对于鸟氨酸，该物种的主要铁载体，我们发现了如何防止欺诈的新机制。特别是，我们发现分泌的鸟氨酸不能被鸟氨酸缺陷型突变体利用，因为鸟氨酸受体和合成基因是在同一操纵子中共同表达的，因此合成基因中的破坏性突变会损害铁载体吸收和作弊所需的受体可用性。对于这个物种的次生铁载体泛铁蛋白，我们发现作弊是可能的，但是作弊者的相对成功是正频率依赖性的，因此与假单胞菌截然相反和其他微生物系统。总而言之，我们的研究结果表明，扩大我们的微生物研究系统范围会带来新的发现，并表明自然界中存在着巨大的社会互动多样性，而到目前为止，我们可能只看过冰山一角。