The Antarctic psychrophiles Chlamydomonas spp. UWO241 and ICE-MDV exhibit differential restructuring of photosystem I in response to iron

Cook, G.G.; Teufel, Amber G.; Kalra, Isha; Li, Wei; Wang, Xin; Priscu, John C.; Morgan‐Kiss, Rachael M.

doi:10.1007/s11120-019-00621-0

Cited by 31 publications

(40 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After a few cycles of light/dark growth, the oxygen evolution rates were measured at the end of the dark period (0 h) and after the light was turned on for 2 h. Error bars indicate the SD; two-tailed Student's t tests were used to compare PSII efficiencies and oxygen evolution rates: *, P , 0.05 and ***, P , 0.001. carbon metabolism (Mullineaux, 2014). We measured the CEF rate through P700 photooxidation under farred (FR) light (Klughammer and Schreiber, 1994;Cook et al, 2019). Oxidized PSI (P700 1 ) absorbs strongly at wavelengths between 810 and 820 nm (A 820 ), while reduced P700 has minimal absorbance at this range.…”

Section: Psi-mediated Cyclic Electron Flow Is Lower In the Glycogen Mmentioning

confidence: 99%

Glycogen Metabolism Supports Photosynthesis Start through the Oxidative Pentose Phosphate Pathway in Cyanobacteria

et al. 2019

Self Cite

View full text Add to dashboard Cite

Cyanobacteria experience drastic changes in their carbon metabolism under daily light/dark cycles. During the day, the Calvin-Benson cycle fixes CO 2 and diverts excess carbon into glycogen storage. At night, glycogen is degraded to support cellular respiration. The dark/light transition represents a universal environmental stress for cyanobacteria and other photosynthetic lifeforms. Recent studies revealed the essential genetic background necessary for the fitness of cyanobacteria during diurnal growth. However, the metabolic processes underlying the dark/light transition are not well understood. In this study, we observed that glycogen metabolism supports photosynthesis in the cyanobacterium Synechococcus elongatus PCC 7942 when photosynthesis reactions start upon light exposure. Compared with the wild type, the glycogen mutant ΔglgC showed a reduced photosynthetic efficiency and a slower P700 1 rereduction rate when photosynthesis starts. Proteomic analyses indicated that glycogen is degraded through the oxidative pentose phosphate (OPP) pathway during the dark/light transition. We confirmed that the OPP pathway is essential for the initiation of photosynthesis and further showed that glycogen degradation through the OPP pathway contributes to the activation of key Calvin-Benson cycle enzymes by modulating NADPH levels. This strategy stimulates photosynthesis in cyanobacteria following dark respiration and stabilizes the Calvin-Benson cycle under fluctuating environmental conditions, thereby offering evolutionary advantages for photosynthetic organisms using the Calvin-Benson cycle for carbon fixation.

show abstract

Section: Psi-mediated Cyclic Electron Flow Is Lower In the Glycogen Mmentioning

confidence: 99%

Glycogen Metabolism Supports Photosynthesis Start through the Oxidative Pentose Phosphate Pathway in Cyanobacteria

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Cyclic electron flow (CEF) around photosystem I (PSI) contributes largely to additional ATP requirements in cyanobacterial carbon metabolism (Mullineaux, 2014). We thus measured the CEF rate through P700 photooxidation under far-red (FR) light(Klughammer and Schreiber, 1994; Cook et al, 2019). Oxidized PSI (P700 + ) absorbs strongly at wavelengths between 810-820 nm (A 820 ), while reduced P700 has minimal absorbance at this range.…”

Section: Resultsmentioning

confidence: 99%

Glycogen metabolism jump-starts photosynthesis through the oxidative pentose phosphate pathway (OPPP) in cyanobacteria

Shinde

Singapuri

Zhang

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

1Cyanobacteria experience drastic changes in their carbon metabolism under daily light-2 dark cycles. In the light, the Calvin-Benson cycle fixes CO 2 and divert excess carbon into 3 glycogen storage. At night, glycogen is degraded to support cellular respiration. Dark-light 4 transition represents a universal environmental stress for cyanobacteria and other photosynthetic 5 lifeforms. Recent studies in the field revealed the essential genetic background necessary for the 6 fitness of cyanobacteria during diurnal growth. However, the metabolic engagement behind the 7 dark-light transition is not well understood. In this study, we discovered that glycogen 8 metabolism can jump-start photosynthesis in the cyanobacterium Synechococcus elongatus PCC 9 7942 when photosynthesis reactions start upon light. Compared to the wild type, the glycogen 10 mutant (∆glgC) showed much lower photosystem II efficiency and slower photosystem I-11 mediated cyclic electron flow rate when photosynthesis starts. Proteomics analyses indicated that 12 glycogen is degraded through the oxidative pentose phosphate pathway (OPPP) during dark-light 13 transition. We confirmed that the OPPP is essential for the initiation of photosynthesis, and 14 further showed that glycogen degradation through the OPPP is likely to contribute to the 15 activation of key Calvin-Benson cycle enzymes by modulating NADPH levels during the 16 transition period. This ingenious strategy helps jump-start photosynthesis in cyanobacteria 17 following dark respiration, and stabilize the Calvin-Benson cycle under fluctuating 18 environmental conditions. It has evolutionary advantages for the survival of photosynthetic 19 organisms using the Calvin-Benson cycle for carbon fixation. 20

show abstract

“…UWO241, on the other hand, belongs to a different chlamydomonadalean clade (the Moewusinia) than ICE-MDV and ICE-L (the Monadinia), and appears to represent a distinct lineage within that clade [6]. Lastly, a recent paper reported that UWO241 and ICE-MDV exhibit additional physiological differences [23].…”

Section: Main Documentmentioning

confidence: 97%

Presence and absence of light-independent chlorophyll biosynthesis among Chlamydomonas green algae in an ice-covered Antarctic lake

Smith

Cvetkovska

Hüner

et al. 2019

Communicative & Integrative Biology

Self Cite

View full text Add to dashboard Cite

The cold, permanently ice-covered waters of Lake Bonney, Antarctica, may seem like an uninviting place for an alga, but they are home to a diversity of photosynthetic life, including Chlamydomonas sp. UWO241, a psychrophile residing in the deep photic zone. Recently, we found that UWO241 has lost the genes responsible for light-independent chlorophyll biosynthesis, which is surprising given that this green alga comes from a light-limited environment and experiences extended periods of darkness during the Antarctic winter. Why discard such a process? We argued that it might be linked to the very high dissolved oxygen concentration of Lake Bonney at the depth at which UWO241 is found. Oxygen is the Achilles' heel of the key enzyme involved in light-independent chlorophyll biosynthesis: DPOR. If this hypothesis is true, then other algae in Lake Bonney should also be susceptible to losing DPOR, such as Chlamydomonas sp. ICE-MDV, which predominantly resides in the chemocline, a depth with an even higher oxygen concentration than that where UWO241 exists. Here, we report that, contrary to our earlier prediction, ICE-MDV has maintained the genes encoding DPOR. We briefly discuss the implications of this finding in relation to the loss of light-independent chlorophyll synthesis in UWO241. ARTICLE HISTORY

show abstract

The Antarctic psychrophiles Chlamydomonas spp. UWO241 and ICE-MDV exhibit differential restructuring of photosystem I in response to iron

Cited by 31 publications

References 93 publications

Glycogen Metabolism Supports Photosynthesis Start through the Oxidative Pentose Phosphate Pathway in Cyanobacteria

Glycogen Metabolism Supports Photosynthesis Start through the Oxidative Pentose Phosphate Pathway in Cyanobacteria

Glycogen metabolism jump-starts photosynthesis through the oxidative pentose phosphate pathway (OPPP) in cyanobacteria

Presence and absence of light-independent chlorophyll biosynthesis among Chlamydomonas green algae in an ice-covered Antarctic lake

Contact Info

Product

Resources

About