Common loss of far-red light photoacclimation in cyanobacteria from hot and cold deserts: a case study in the Chroococcidiopsidales.
Common loss of far-red light photoacclimation in cyanobacteria from hot and cold deserts: a case study in the Chroococcidiopsidales.
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DOI：
10.1038/s43705-023-00319-4
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发表时间：
2023-10-19
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影响因子：
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通讯作者：
Nurnberg, Dennis J
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作者：
Antonaru, Laura A;Selinger, Vera M;Jung, Patrick;Di Stefano, Giorgia;Sanderson, Nicholas D;Barker, Leanne;Wilson, Daniel J;Budel, Burkhard;Canniffe, Daniel P;Billi, Daniela;Nurnberg, Dennis J
沙漠对光合生物来说是一个极端的挑战。尽管它们很干燥，但它们经常被各种微观的蓝藻群落所居住。这些生物通常在岩石栖息地中发现，在那里它们部分受到极端温度和紫外线辐射的保护。然而，生活在岩石表面下会带来额外的限制，比如有限的光可用性，以及比通常用于氧光合作用的波长更长的富集。一些来自绿球藻属的蓝藻可以利用这种光进行光合作用，这一过程被称为远红光光驯化（FaRLiP）。这个属通常在炎热和寒冷的沙漠中都有报道。然而，并非所有的球藻菌株都携带FaRLiP基因，因此促使我们研究FaRLiP与极端岩石环境之间的相互作用。丰富的序列数据和菌株为深入的系统发育研究提供了必要的材料，包括光谱、显微镜、色素成分测定以及基因和基因组分析。色素分析显示，在所有测试的FaRLiP菌株中存在红移叶绿素d和f。此外，在包络的绒球亚目中定义了8个属级分类群，阐明了这一长期存在的多系目的系统发育。FaRLiP几乎普遍存在于一个广泛存在于各种环境的通用属中，即严格意义的Chroococcidiopsis sensu stricto，而在密切相关的极端生物分类群中则很少或不存在，包括那些优先居住在沙漠中的物种。这可能反映了基因在特殊谱系中丢失的进化过程。
Deserts represent an extreme challenge for photosynthetic life. Despite their aridity, they are often inhabited by diverse microscopic communities of cyanobacteria. These organisms are commonly found in lithic habitats, where they are partially sheltered from extremes of temperature and UV radiation. However, living under the rock surface imposes additional constraints, such as limited light availability, and enrichment of longer wavelengths than are typically usable for oxygenic photosynthesis. Some cyanobacteria from the genus Chroococcidiopsis can use this light to photosynthesize, in a process known as far-red light photoacclimation, or FaRLiP. This genus has commonly been reported from both hot and cold deserts. However, not all Chroococcidiopsis strains carry FaRLiP genes, thus motivating our study into the interplay between FaRLiP and extreme lithic environments. The abundance of sequence data and strains provided the necessary material for an in-depth phylogenetic study, involving spectroscopy, microscopy, and determination of pigment composition, as well as gene and genome analyses. Pigment analyses revealed the presence of red-shifted chlorophylls d and f in all FaRLiP strains tested. In addition, eight genus-level taxa were defined within the encompassing Chroococcidiopsidales, clarifying the phylogeny of this long-standing polyphyletic order. FaRLiP is near universally present in a generalist genus identified in a wide variety of environments, Chroococcidiopsis sensu stricto, while it is rare or absent in closely related, extremophile taxa, including those preferentially inhabiting deserts. This likely reflects the evolutionary process of gene loss in specialist lineages.