Substantial near-infrared radiation-driven photosynthesis of chlorophyll f-containing cyanobacteria in a natural habitat

Abstract

Far-red absorbing chlorophylls are constitutively present as chlorophyll (Chl) d in the cyanobacterium Acaryochloris marina, or dynamically expressed by synthesis of Chl f, red-shifted phycobiliproteins and minor amounts of Chl d via far-red light photoacclimation in a range of cyanobacteria, which enables them to use near-infrared-radiation (NIR) for oxygenic photosynthesis. While the biochemistry and molecular physiology of Chl f-containing cyanobacteria has been unraveled in culture studies, their ecological significance remains unexplored and no data on their in situ activity exist. With a novel combination of hyperspectral imaging, confocal laser scanning microscopy, and nanoparticle-based O2 imaging, we demonstrate substantial NIR-driven oxygenic photosynthesis by endolithic, Chl f-containing cyanobacteria within natural beachrock biofilms that are widespread on (sub)tropical coastlines. This indicates an important role of NIR-driven oxygenic photosynthesis in primary production of endolithic and other shaded habitats.

Opportunities and challenges for assigning cofactors in cryo-EM density maps of chlorophyll-containing proteins

“…FRL photoacclimation, or “FaRLiP” 48 , confers the ability for cyanobacteria to absorb FRL 49 , the energy of which is converted to chemical energy by their photochemical oxidoreductases PSI and PSII. FaRLiP allows organisms to thrive in shaded environments where FRL is prevalent, such as soils 50 , microbial mats 51 , photic zones of caves 52 , stromatolites 53 , and biofilms associated with beachrock 54 , 55 . Cyanobacteria are especially important primary producers of organic carbon 56 ; therefore, understanding the way in which they have adapted and can acclimate to various environments provides insight into novel biological mechanisms that may be used to engineer FRL absorption into oxygenic phototrophs that generally grow slowly in shaded environments 57 , 58 .…”

Imaging O2 dynamics and microenvironments in the seagrass leaf phyllosphere with magnetic optical sensor nanoparticles

“…Unfavourable water-column conditions such as heatwaves and ocean deoxygenation (predicted in future climate scenarios) may exacerbate the occurrence and detrimental effects of these anoxic microniches in the seagrass leaf microenvironment, especially at night, leading to increased die-off events in exposed areas (Borum et al, 2005(Borum et al, , 2006Pedersen et al, 2016). In the subsurface layers of the epiphytic biofilm, hot spots for microbial activity may include shaded microhabitats with high photosynthetic productivity driven by cyanobacteria with chlorophyll d and f using near-infrared light (>700 nm) for oxygenic photosynthesis (Kühl et al, 2020). Such ecological niches in the micro-understory of the epiphytic biofilm could be targeted for pigment analysis and amplicon sequencing (Figure 4; Kühl et al, 2020), elucidating the potential importance for such shaded microhabitats below the epiphytic microalgal canopies.…”

“…In the subsurface layers of the epiphytic biofilm, hot spots for microbial activity may include shaded microhabitats with high photosynthetic productivity driven by cyanobacteria with chlorophyll d and f using near‐infrared light (>700 nm) for oxygenic photosynthesis (Kühl et al ., 2020). Such ecological niches in the micro‐understory of the epiphytic biofilm could be targeted for pigment analysis and amplicon sequencing (Figure 4; Kühl et al ., 2020), elucidating the potential importance for such shaded microhabitats below the epiphytic microalgal canopies.…”

Non-toxic near-infrared light-emitting diodes

“…This review starts by discussing the motivations for non-toxic materials (Section 2), we then recall different approaches to generate and promote NIR emission (Section 3), and summarize recent achievements in the development of highly efficient NIR LEDs, Figure 1. Schematic illustration for the application of NIR LEDs (Kü hl et al, 2020;Haigh et al, 2015;Neuman et al, 2015;Veldhuis et al, 2020). iScience Review with special attention to lead-free perovskite materials, thermally activated delayed fluorescence (TADF) molecules, as well as aggregation-induced emission-active fluorophores (Section 4).…”

“…Furthermore, NIR radiation is virtually invisible to the human eye, and by expanding the available bandwidth, NIR LEDs are excellent candidates for integration as transmitters in visible light communication links, as recently reported by our group ( Haigh et al., 2015 ; Minotto et al., 2020 ; Le et al., 2014 ) and others.

Figure 1 Schematic illustration for the application of NIR LEDs ( Kühl et al., 2020 ; Haigh et al., 2015 ; Neuman et al., 2015 ; Veldhuis et al., 2020 ).

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