Data from: Entangled fates of holobiont genomes during invasion: nested bacterial and host diversities in Caulerpa taxifolia

Successful prevention and mitigation of biological invasions requires retracing the initial steps of introduction, as well as understanding key elements enhancing the adaptability of invasive species. We studied the genetic diversity of the green alga Caulerpa taxifolia and its associated bacterial communities in several areas around the world. The striking congruence of α and ß diversity of the algal genome and endophytic communities reveals a tight association, supporting the holobiont concept as best describing the unit of spreading and invasion. Both genomic compartments support the hypotheses of a unique accidental introduction in the Mediterranean and of multiple invasion events in Southern Australia. In addition to helping with tracing the origin of invasion, bacterial communities exhibit metabolic functions that can potentially enhance adaptability and competitiveness of the consortium they form with their host. We thus hypothesize that low genetic diversities of both host and symbiont communities may contribute to the recent regression in the Mediterranean, in contrast with the persistence of highly diverse assemblages in southern Australia. This study supports the importance of scaling up from the host to the holobiont for a comprehensive understanding of invasions.

要成功防控生物入侵，既需回溯其初始传入路径，也需明确提升入侵物种适应性的关键要素。我们对全球多个区域的杉叶蕨藻（Caulerpa taxifolia）及其相关细菌群落开展了遗传多样性研究。藻类基因组与内生细菌群落的α、β多样性呈现高度一致的分布模式，表明二者存在紧密关联，这一结果支持以全共生体（holobiont）作为描述物种扩散与入侵的基本单元的观点。两类基因组组分均支持两个假说：一是地中海区域仅存在单次偶然传入事件，二是澳大利亚南部存在多起入侵事件。除了有助于溯源入侵起源外，细菌群落还具备代谢功能，可提升其与宿主形成的共生联合体的适应性与竞争能力。据此我们提出假说：与澳大利亚南部保持高度多样的群落组合不同，地中海区域宿主与共生群落的低遗传多样性可能是导致其近期种群衰退的原因。本研究表明，若要全面解析生物入侵机制，需将研究尺度从宿主拓展至全共生体层面，这一思路具有重要意义。