Westley Joseph, García Francisca C, Warfield Ruth, Yvon-Durocher Gabriel
Environment and Sustainability Institute, The Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, United Kingdom.
Red Sea Research Center (RSRC), Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
Evol Lett. 2024 Mar 16;8(4):505-513. doi: 10.1093/evlett/qrae007. eCollection 2024 Aug.
Microbes are key drivers of global biogeochemical cycles, and their functional roles arey dependent on temperature. Large population sizes and rapid turnover rates mean that the predominant response of microbes to environmental warming is likely to be evolutionary, yet our understanding of evolutionary responses to temperature change in microbial systems is rudimentary. Natural microbial communities are diverse assemblages of interacting taxa. However, most studies investigating the evolutionary response of bacteria to temperature change are focused on monocultures. Here, we utilize high-throughput experimental evolution of bacteria in both monoculture and community contexts along a thermal gradient to determine how interspecific interactions influence the thermal adaptation of community members. We found that community-evolved isolates tended toward higher maximum growth rates across the temperature gradient compared to their monoculture-evolved counterparts. We also saw little evidence of systematic evolutionary change in the shapes of bacterial thermal tolerance curves along the thermal gradient. However, the effect of community background and selection temperature on the evolution of thermal tolerance curves was variable and highly taxon-specific,with some taxa exhibiting pronounced changes in thermal tolerance while others were less impacted. We also found that temperature acted as a strong environmental filter, resulting in the local extinction of taxa along the thermal gradient, implying that temperature-driven ecological change was a key factor shaping the community background upon which evolutionary selection can operate. These findings offer novel insight into how community background impacts thermal adaptation.
微生物是全球生物地球化学循环的关键驱动因素，其功能作用取决于温度。庞大的种群规模和快速的周转率意味着微生物对环境变暖的主要反应可能是进化性的，然而我们对微生物系统中温度变化的进化反应的理解还很初步。自然微生物群落是相互作用的分类群的多样化组合。然而，大多数研究细菌对温度变化的进化反应的研究都集中在单一培养物上。在这里，我们利用细菌在单一培养和群落环境中沿热梯度的高通量实验进化，来确定种间相互作用如何影响群落成员的热适应性。我们发现，与单一培养进化的菌株相比，群落进化的菌株在整个温度梯度上倾向于具有更高的最大生长速率。我们也几乎没有发现细菌耐热曲线形状沿热梯度有系统进化变化的证据。然而，群落背景和选择温度对耐热曲线进化的影响是可变的，且高度依赖于分类群，一些分类群的耐热性有显著变化，而另一些则受影响较小。我们还发现温度起到了强大的环境筛选作用，导致分类群沿热梯度局部灭绝，这意味着温度驱动的生态变化是塑造进化选择得以运作的群落背景的关键因素。这些发现为群落背景如何影响热适应性提供了新的见解。
