Contrasting nonphotochemical quenching patterns under high light and darkness aligns with light niche occupancy in Arctic diatoms
Contrasting nonphotochemical quenching patterns under high light and darkness aligns with light niche occupancy in Arctic diatoms
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DOI：
10.1002/lno.11587
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发表时间：
2020-09-02
影响因子：
4.5
通讯作者：
Lavaud, Johann
中科院分区：
文献类型：
--
作者：
Croteau, Dany;Guerin, Sebastien;Lavaud, Johann
随着季节的推移，北极硅藻物种占据着由对比鲜明的光照气候所定义的不断变化的栖息地，受到冰雪覆盖动态与极端光照周期和太阳角度变化的相互作用的限制。北极硅藻的光适应策略如何在其异质的光生态位中有所不同，仍然是一个记录不多但关键的缺失环节，以预测北冰洋对海冰萎缩和光照增加的反应。为了解决这个问题，我们选择了五个北极硅藻物种不同的生活特征，代表不同的光生态位的季节性光环境连续体：从积雪覆盖的昏暗的底部冰到夏季分层的沃茨。我们研究了它们对两种生长光水平的光适应可塑性，以及它们的非光化学猝灭（NPQ）和叶黄素循环对暗培养和光转移的响应。我们破译了NPQ和叶黄素循环在黑暗中的调谐和它们的光依赖诱导动力学，这与物种的光生态位占用一致。在冰相关的物种，NPQ持续在黑暗中，其诱导更反应温和的光变化。开放水域的物种在黑暗中引发强烈的NPQ诱导，并在强光下达到较高的最大NPQ。边缘冰区物种表现出强烈的适应光的波动与黑暗的响应微调取决于光的历史。我们认为，这些特点是锚定在不同的光适应策略，促进北极硅藻在各自的光生态位的成功。
Over the seasons, Arctic diatom species occupy shifting habitats defined by contrasting light climates, constrained by snow and ice cover dynamics interacting with extreme photoperiod and solar angle variations. How Arctic diatom photoadaptation strategies differ across their heterogeneous light niches remains a poorly documented but crucial missing link to anticipate Arctic Ocean responses to shrinking sea-ice and increasing light. To address this question, we selected five Arctic diatom species with diverse life traits, representative of distinct light niches across the seasonal light environment continuum: from snow-covered dimly lit bottom ice to summer stratified waters. We studied their photoacclimation plasticity to two growth light levels and the subsequent responses of their nonphotochemical quenching (NPQ) and xanthophyll cycle to both dark incubations and light shifts. We deciphered NPQ and xanthophyll cycle tuning in darkness and their light-dependent induction kinetics, which aligned with species' light niche occupancy. In ice-related species, NPQ was sustained in darkness and its induction was more reactive to moderate light shifts. Open-water species triggered strong NPQ induction in darkness and reached higher maximal NPQ under high light. Marginal ice zone species showed strong adaptation to light fluctuations with a dark response fine-tuned depending upon light history. We argue these traits are anchored in diverging photoadaption strategies fostering Arctic diatom success in their respective light niches.