Antimicrobial peptides (AMPs) are massively produced by eukaryotic hosts during symbiotic interactions with bacteria. Among other roles, these symbiotic AMPs have the capacity to permeabilize symbiont membranes and facilitate metabolite flow across the host–symbiont interface. We propose that an ancestral role of these peptides is to facilitate metabolic exchange between the symbiotic partners through membrane permeabilization. This function may be particularly critical for integration of endosymbiont and host metabolism in interactions involving bacteria with strongly reduced genomes lacking most small metabolite transporters. Moreover, AMPs could have acted in a similar way at the onset of plastid and mitochondrion evolution, after a host cell took up a bacterium and needed to extract nutrients from it in the absence of dedicated solute transporters.

真核宿主在与细菌共生的过程中大量产生抗菌肽（AMP）。这些共生AMP除其他作用外，还具有透化共生膜并促进代谢物跨宿主-共生体界面流动的能力。我们提出这些肽的祖先作用是通过膜透化促进共生伴侣之间的代谢交换。该功能对于整合胞内共生体和宿主代谢在涉及细菌而基因组强烈减少而缺乏大多数小代谢物转运蛋白的相互作用中可能特别重要。此外，AMP在质体和线粒体进化开始时可能以类似的方式起作用，