In the context of global warming, this study aimed to assess the effect of temperature and irradiance on the macroalgal Taonia atomaria holobiont dynamics. We developed an experimental set-up using aquaria supplied by natural seawater with three temperatures combined with three irradiances. The holobiont response was monitored over 14 days using a multi-omics approach coupling algal surface metabolomics and metabarcoding. Both temperature and irradiance appeared to shape the microbiota and the surface metabolome, but with a distinct temporality. Epibacterial community first changed according to temperature, and later in relation to irradiance, while the opposite occurred for the surface metabolome. An increased temperature revealed a decreasing richness of the epiphytic community together with an increase of several bacterial taxa. Irradiance changes appeared to quickly impact surface metabolites production linked with the algal host photosynthesis (e.g. mannitol, fucoxanthin, dimethylsulfoniopropionate), which was hypothesized to explain modifications of the structure of the epiphytic community. Algal host may also directly adapt its surface metabolome to changing temperature with time (e.g. lipids content) and also in response to changing microbiota (e.g. chemical defences). Finally, this study brought new insights highlighting complex direct and indirect responses of seaweeds and their associated microbiota under changing environments.

中文翻译：

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温度和光的协同效应影响Taoniaatomaria与其表细菌群落之间的关系：一项受控条件研究


在全球变暖的背景下，本研究旨在评估温度和辐照度对大型藻类Taoniaatomariaholobiont动力学的影响。我们开发了一个实验装置，使用由天然海水提供的水族箱，具有三种温度和三种辐照度。使用结合藻类表面代谢组学和元条形码的多组学方法对全生物反应进行了 14 天的监测。温度和辐照度似乎都会塑造微生物群和表面代谢组，但具有明显的时间性。表观细菌群落首先根据温度而变化，然后根据辐照度而变化，而表面代谢组则发生相反的情况。温度升高表明附生群落的丰富度下降，同时一些细菌类群的增加。辐照度变化似乎会快速影响与藻类宿主光合作用相关的表面代谢物的产生（例如甘露醇、岩藻黄质、二甲磺酰基丙酸酯），这被假设可以解释附生群落结构的变化。藻类宿主还可以直接调整其表面代谢组以适应随时间变化的温度（例如脂质含量）以及响应微生物群的变化（例如化学防御）。最后，这项研究带来了新的见解，强调了海藻及其相关微生物群在不断变化的环境下复杂的直接和间接反应。