A niche for cyanobacteria containing chlorophyll d. Nature 433:820

Marine Biological Laboratory, Institute of Biology, University of Copenhagen, 3000 Helsingør, Denmark.
Nature (Impact Factor: 41.46). 03/2005; 433(7028):820. DOI: 10.1038/433820a
Source: PubMed


The cyanobacterium known as Acaryochloris marina is a unique phototroph that uses chlorophyll d as its principal light-harvesting pigment instead of chlorophyll a, the form commonly found in plants, algae and other cyanobacteria; this means that it depends on far-red light for photosynthesis. Here we demonstrate photosynthetic activity in Acaryochloris-like phototrophs that live underneath minute coral-reef invertebrates (didemnid ascidians) in a shaded niche enriched in near-infrared light. This discovery clarifies how these cyanobacteria are able to thrive as free-living organisms in their natural habitat.

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Available from: Michael Kühl
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    • "A radical redesign of the photosynthetic apparatus for both bioenergy and food production application may be realized utilizing techniques in synthetic biology to engineer the photosystem in energy storage and RuBisCo in carbon fixation (Blankenship et al. 2011). Among prokaryotic photosynthetic cyanobacteria, A. marina is a unique phototroph that uses Chl d as its principle light-harvesting pigment instead of Chl a (Akiyama et al. 2001; Kuhl et al. 2005). The minor difference in the structure of Chl d, C3-formyl group on ring 1, compared with the vinyl group of Chl a, results in Chl d having an absorption peak more red-shift than Chl a in acetone which is shifted about 30 nm compared to Chl a (Hu et al. 1998; Chen et al. 2002). "
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    ABSTRACT: We have previously investigated the response mechanisms of photosystem II complexes from spinach to strong UV and visible irradiations (Wei et al J Photochem Photobiol B 104:118-125, 2011). In this work, we extend our study to the effects of strong light on the unusual cyanobacterium Acaryochloris marina, which is able to use chlorophyll d (Chl d) to harvest solar energy at a longer wavelength (740 nm). We found that ultraviolet (UV) or high level of visible and near-far red light is harmful to A. marina. Treatment with strong white light (1,200 μmol quanta m(-2) s(-1)) caused a parallel decrease in PSII oxygen evolution of intact cells and in extracted pigments Chl d, zeaxanthin, and α-carotene analyzed by high-performance liquid chromatography, with severe loss after 6 h. When cells were irradiated with 700 nm of light (100 μmol quanta m(-2) s(-1)) there was also bleaching of Chl d and loss of photosynthetic activity. Interestingly, UVB radiation (138 μmol quanta m(-2) s(-1)) caused a loss of photosynthetic activity without reduction in Chl d. Excess absorption of light by Chl d (visible or 700 nm) causes a reduction in photosynthesis and loss of pigments in light harvesting and photoprotection, likely by photoinhibition and inactivation of photosystem II, while inhibition of photosynthesis by UVB radiation may occur by release of Mn ion(s) in Mn4CaO5 center in photosystem II.
    Full-text · Article · Oct 2013 · Photosynthesis Research
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    • "Acaryochloris, another atypical cyanobacterium frequently found in association with Prochloron contains yet another major pigment, Chl d, a unique chromophore that absorbs near-infrared light (Miyashita et al. 1997). It is worth noting that Acaryochloris was initially thought to be an endosymbiont of ascidians (Miyashita et al. 2003), but a more recent analysis showed that is in fact a free-living epiphyte of those invertebrates (Kuhl et al. 2005) and it has been retrieved subsequently in a variety of benthic environments, including from underneath the crust of coralline algae living in coral reefs (Behrendt et al. 2010; Mohr et al. 2010a). While Prochloron has never been cultivated, several Acaryochloris has been successfully brought into culture and three strains have been sequenced to date (Swingley et al. 2008; Mohr et al. 2010a; Pfreundt et al. 2012). "
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    ABSTRACT: Environmental (ecological) genomics aims to understand the genetic basis of relationships between organisms and their abiotic and biotic environments. It is a rapidly progressing field of research largely due to recent advances in the speed and volume of genomic data being produced by next generation sequencing (NGS) technologies. Building on information generated by NGS-based approaches, functional genomic methodologies are being applied to identify and characterize genes and gene systems of both environmental and evolutionary relevance. Marine photosynthetic organisms (MPOs) were poorly represented amongst the early genomic models, but this situation is changing rapidly. Here we provide an overview of the recent advances in the application of ecological genomic approaches to both prokaryotic and eukaryotic MPOs. We describe how these approaches are being used to explore the biology and ecology of marine cyanobacteria and algae, particularly with regard to their functions in a broad range of marine ecosystems. Specifically, we review the ecological and evolutionary insights gained from whole genome and transcriptome sequencing projects applied to MPOs and illustrate how their genomes are yielding information on the specific features of these organisms.
    Full-text · Article · Feb 2013 · Molecular Ecology
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    • "The cyanobacteria Acaryochloris sp., a common epiphyte of major macroalgae [50] and a symbiont of the colonial ascidians [51], was found in one of the sponges sampled from Praia de São Bartolomeu do Mar (sponge ID- HYM16B) (Figure 5). The oxygenic photoautotroph Acaryochloris sp. was widely detected as a symbiont in ascidians [52], [53]. Relatively high frequency of Synechococcus sp. and uncultured marine cyanobacteria throughout the sponges sampled suggested the co-existence of multiple symbiotic partners. "
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    ABSTRACT: Cyanobacteria represent one of the most common members of the sponge-associated bacterial community and are abundant symbionts of coral reef ecosystems. In this study we used Transmission Electron Microscopy (TEM) and molecular techniques (16S rRNA gene marker) to characterize the spatial distribution of cyanobionts in the widely dispersed marine intertidal sponge Hymeniacidon perlevis along the coast of Portugal (Atlantic Ocean). We described new sponge associated cyanobacterial morphotypes (Xenococcus-like) and we further observed Acaryochloris sp. as a sponge symbiont, previously only reported in association with ascidians. Besides these two unique cyanobacteria, H. perlevis predominantly harbored Synechococcus sp. and uncultured marine cyanobacteria. Our study supports the hypothesis that the community of sponge cyanobionts varies irrespective of the geographical location and is likely influenced by seasonal fluctuations. The observed multiple cyanobacterial association among sponges of the same host species over a large distance may be attributed to horizontal transfer of symbionts. This may explain the absence of a co-evolutionary pattern between the sponge host and its symbionts. Finally, in spite of the short geographic sampling distance covered, we observed an unexpected high intra-specific genetic diversity in H. perlevis using the mitochondrial genes ATP6 (π = 0.00177), COI (π = 0.00241) and intergenic spacer SP1 (π = 0.00277) relative to the levels of genetic variation of marine sponges elsewhere. Our study suggests that genotypic variation among the sponge host H. perlevis and the associated symbiotic cyanobacteria diversity may be larger than previously recognized.
    Full-text · Article · Dec 2012 · PLoS ONE
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