| Autor: |
Caspari, OD, Meyer, MT, Tolleter, D, Wittkopp, TM, Cunniffe, NJ, Lawson, T, Grossman, AR, Griffiths, H |
| Přispěvatelé: |
Cunniffe, Nik [0000-0002-3533-8672], Griffiths, Howard [0000-0002-3009-6563], Apollo - University of Cambridge Repository |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
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| Popis: |
The pyrenoid of the unicellular green alga Chlamydomonas reinhardtii is a microcompartment situated in the centre of the cup-shaped chloroplast, containing up to 90% of cellular Rubisco. Traversed by a network of dense, knotted thylakoid tubules, the pyrenoid has been proposed to influence thylakoid biogenesis and ultrastructure. Mutants that are unable to assemble a pyrenoid matrix, due to expressing a vascular plant version of the Rubisco small subunit, exhibit severe growth and photosynthetic defects and have an ineffective carbon-concentrating mechanism (CCM). The present study set out to determine the cause of photosynthetic limitation in these pyrenoid-less lines. We tested whether electron transport and light use were compromised as a direct structural consequence of pyrenoid loss or as a metabolic effect downstream of lower CCM activity and resulting CO₂ limitation. Thylakoid organization was unchanged in the mutants, including the retention of intrapyrenoid-type thylakoid tubules, and photosynthetic limitations associated with the absence of the pyrenoid were rescued by exposing cells to elevated CO₂ levels. These results demonstrate that Rubisco aggregation in the pyrenoid functions as an essential element for CO₂ delivery as part of the CCM, and does not play other roles in maintenance of photosynthetic membrane energetics. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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