Light color acclimation is a key process in the global ocean distribution of Synechococcus cyanobacteria
Light color acclimation is a key process in the global ocean distribution of Synechococcus cyanobacteria
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DOI：
10.1073/pnas.1717069115
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发表时间：
2018-02-27
影响因子：
11.1
通讯作者：
Garczarek, Laurence
中科院分区：
文献类型：
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作者：
Grebert, Theophile;Dore, Hugo;Garczarek, Laurence
海洋聚球藻蓝藻是全球海洋初级生产的主要贡献者，并表现出独特的光合色素多样性，使它们能够利用广泛的光生态位。然而，色素含量和生态位分配之间的关系仍然在很大程度上不确定，由于缺乏一个单一的遗传标记解决所有的色素类型（PT）。在这里，我们开发并采用了一种基于三种不同标记基因（cpcBA，mpeBA和mpeW）的稳健方法来估计宏基因组中所有已知聚球藻PT的相对丰度。对塔拉海洋数据集的分析使我们能够揭示聚球藻PT的全球分布并定义其环境生态位。绿光专家（PT 3a）占主导地位的温暖，绿色赤道沃茨，而蓝光专家（PT 3c）特别丰富的贫营养区。IV型色适应者（CA 4-A/B）能够动态地改变其光吸收特性以最大限度地吸收绿色或蓝色光，出乎意料地是我们数据集中最丰富的PT，并且在深度和高纬度地区占主导地位。我们还确定了由于缺乏特定的CA 4基因，特别是在温暖的高营养低叶绿素地区，CA 4可能是非功能性的人群。分支I-IV和CRD 1内的主要生态型优先与特定的PT，而其他表现出广泛的PT。总之，这项研究提供了重要的见解聚球藻的生态，并强调了复杂的相互作用之间的垂直发育，色素沉着，和环境参数，形状聚球藻群落结构和进化。
Marine Synechococcus cyanobacteria are major contributors to global oceanic primary production and exhibit a unique diversity of photosynthetic pigments, allowing them to exploit a wide range of light niches. However, the relationship between pigment content and niche partitioning has remained largely undetermined due to the lack of a single-genetic marker resolving all pigment types (PTs). Here, we developed and employed a robust method based on three distinct marker genes (cpcBA, mpeBA, and mpeW) to estimate the relative abundance of all known Synechococcus PTs from metagenomes. Analysis of the Tara Oceans dataset allowed us to reveal the global distribution of Synechococcus PTs and to define their environmental niches. Green-light specialists (PT 3a) dominated in warm, green equatorial waters, whereas blue-light specialists (PT 3c) were particularly abundant in oligotrophic areas. Type IV chromatic acclimaters (CA4-A/B), which are able to dynamically modify their light absorption properties to maximally absorb green or blue light, were unexpectedly the most abundant PT in our dataset and predominated at depth and high latitudes. We also identified populations in which CA4 might be nonfunctional due to the lack of specific CA4 genes, notably in warm high-nutrient low-chlorophyll areas. Major ecotypes within clades I-IV and CRD1 were preferentially associated with a particular PT, while others exhibited a wide range of PTs. Altogether, this study provides important insights into the ecology of Synechococcus and highlights the complex interactions between vertical phylogeny, pigmentation, and environmental parameters that shape Synechococcus community structure and evolution.