Evidence for evolutionary adaptation of mixotrophic nanoflagellates to warmer temperatures.
Evidence for evolutionary adaptation of mixotrophic nanoflagellates to warmer temperatures.
复制标题
DOI：
10.1111/gcb.16431
复制
发表时间：
2022-12
影响因子：
11.6
通讯作者：
中科院分区：
文献类型：
--
作者：
混合营养体是一种结合光合作用和异养以获取能量的生物，在全球生物地球化学循环中发挥着重要作用。代谢理论预测，随着温度的升高，混合营养体将变得更加异养，这可能会形成一个正反馈循环，加速大气中二氧化碳的积累。验证这一理论的研究主要集中在混合营养体的表型塑性（短期、非进化）热反应上。然而，混合营养型生物作为一种世代时间短、种群规模大的小型生物，可能会在气候变化的影响下迅速进化。在这里，我们展示了一项为期3年的实验数据，该实验量化了两种混合营养纳米鞭毛虫对温度的进化反应。我们在专性光养菌株中发现了适应性进化的证据（相对于驯化谱系，进化谱系的生长速度增加），但在兼性光养菌株中却没有。所有谱系均表现出碳利用效率提高、热反应规范变平以及基因表达回归稳态的趋势。一般来说，随着温度的升高，混合营养体的光合作用减少，放牧增加，这表明进化可能会加剧混合营养体对全球碳循环的影响。混合营养代谢结合了异养和光养，两者都依赖于温度。随着温度的升高，异养可能会受到青睐，这可能会推动加速变暖的气候反馈。我们在低温和高温条件下实验进化了两株海洋混合营养嗜色单胞菌，并将进化菌株与对照菌株进行了比较。我们的研究结果表明，一种菌株适应迅速，在不同温度下表现出相似的基因表达，并且更多地放牧而更少地进行光合作用。每种菌株都以自己的方式做出反应。因此，虽然混合营养体可能会迅速进化以应对气候变化，但反应可能是可变的，难以预测。
Mixotrophs, organisms that combine photosynthesis and heterotrophy to gain energy, play an important role in global biogeochemical cycles. Metabolic theory predicts that mixotrophs will become more heterotrophic with rising temperatures, potentially creating a positive feedback loop that accelerates carbon dioxide accumulation in the atmosphere. Studies testing this theory have focused on phenotypically plastic (short‐term, non‐evolutionary) thermal responses of mixotrophs. However, as small organisms with short generation times and large population sizes, mixotrophs may rapidly evolve in response to climate change. Here, we present data from a 3‐year experiment quantifying the evolutionary response of two mixotrophic nanoflagellates to temperature. We found evidence for adaptive evolution (increased growth rates in evolved relative to acclimated lineages) in the obligately phototrophic strain, but not in the facultative phototroph. All lineages showed trends of increased carbon use efficiency, flattening of thermal reaction norms, and a return to homeostatic gene expression. Generally, mixotrophs evolved reduced photosynthesis and higher grazing with increased temperatures, suggesting that evolution may act to exacerbate mixotrophs' effects on global carbon cycling. Mixotroph metabolism combines heterotrophy and phototrophy, both of which are temperature dependent. Heterotrophy may be favored as temperatures rise, which could drive climate feedbacks that accelerate warming. We experimentally evolved two strains of the marine mixotroph Ochromonas at cold and hot temperatures and compared evolved strains to control strains. Our results show that one strain adapted rapidly, showed similar gene expressions across temperatures, and did more grazing and less photosynthesis. Each strain responded in its own way. So, although mixotrophs are likely to evolve rapidly in response to changing climate, responses may be variable and hard to predict.
登录
查看更多内容
影响因子：
30.7
作者：
Brennan, Georgina;Collins, Sinead
通讯作者：
Collins, Sinead
DOI：
10.1073/pnas.1703375114
发表时间：
2017-09-12
影响因子：
11.1
作者：
Brennan, Georgina L.;Colegrave, Nick;Collins, Sinead
通讯作者：
Collins, Sinead
影响因子：
1.7
作者：
Bankevich, Anton;Nurk, Sergey;Pevzner, Pavel A.
通讯作者：
Pevzner, Pavel A.
影响因子：
3.7
作者：
Gorbunov, MY;Kolber, ZS;Falkowski, PG
通讯作者：
Falkowski, PG
影响因子：
4.1
作者：
Collins S;Rost B;Rynearson TA
通讯作者：
Rynearson TA