Comparative Thermophysiology of Marine Synechococcus CRD1 Strains Isolated From Different Thermal Niches in Iron-Depleted Areas.
Comparative Thermophysiology of Marine Synechococcus CRD1 Strains Isolated From Different Thermal Niches in Iron-Depleted Areas.
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DOI：
10.3389/fmicb.2022.893413
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发表时间：
2022
影响因子：
5.2
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中科院分区：
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海洋聚球藻蓝藻在海洋中普遍存在，这一特征可能与其广泛的遗传多样性有关。在主要谱系中，分支I和IV优先在温带和寒冷的、营养丰富的沃茨中茁壮成长，而分支II和III则喜欢温暖的、氮或磷耗尽的沃茨。这种冷（I/IV）和暖（II/III）热型的存在是由代表性菌株的生理特征所证实的。第五支，CRD 1，最近被证明占主导地位的聚球藻社会在铁贫化地区的世界海洋，并包括三个不同的生态重要的分类单位（ESTUs CRD 1A-C）占据不同的热生态位，这表明不同的热型也可能发生在这个分支。在这里，使用这三个CRD 1 ESTUs的代表菌株的比较热生理学，我们表明，CRD 1A株MITS 9220是一个温暖的热型，CRD 1B株BIOS-U3-1的冷温带热型，和CRD 1C株BIOS-E4-1的暖温带狭窄。奇怪的是，CRD 1B热型缺乏冷热型的典型特征和/或基因组特征。相比之下，我们发现特定的生理特性的CRD 1菌株相比，他们的进化枝I，II，III，和IV的同行，包括较低的生长速度和光系统II的最大量子产率在大多数温度和较高的周转率的D1蛋白。总之，我们的数据表明，CRD 1进化枝优先适应低铁条件下的温度适应，即使发生几个CRD 1热型可能解释了为什么CRD 1进化枝作为一个整体占据大多数铁有限的沃茨。
Marine Synechococcus cyanobacteria are ubiquitous in the ocean, a feature likely related to their extensive genetic diversity. Amongst the major lineages, clades I and IV preferentially thrive in temperate and cold, nutrient-rich waters, whilst clades II and III prefer warm, nitrogen or phosphorus-depleted waters. The existence of such cold (I/IV) and warm (II/III) thermotypes is corroborated by physiological characterization of representative strains. A fifth clade, CRD1, was recently shown to dominate the Synechococcus community in iron-depleted areas of the world ocean and to encompass three distinct ecologically significant taxonomic units (ESTUs CRD1A-C) occupying different thermal niches, suggesting that distinct thermotypes could also occur within this clade. Here, using comparative thermophysiology of strains representative of these three CRD1 ESTUs we show that the CRD1A strain MITS9220 is a warm thermotype, the CRD1B strain BIOS-U3-1 a cold temperate thermotype, and the CRD1C strain BIOS-E4-1 a warm temperate stenotherm. Curiously, the CRD1B thermotype lacks traits and/or genomic features typical of cold thermotypes. In contrast, we found specific physiological traits of the CRD1 strains compared to their clade I, II, III, and IV counterparts, including a lower growth rate and photosystem II maximal quantum yield at most temperatures and a higher turnover rate of the D1 protein. Together, our data suggests that the CRD1 clade prioritizes adaptation to low-iron conditions over temperature adaptation, even though the occurrence of several CRD1 thermotypes likely explains why the CRD1 clade as a whole occupies most iron-limited waters.