Abstract
C4 photosynthesis requires more ATP than C3 photosynthesis to drive the C4 cycle, which concentrates CO2 in the bundle sheath cells. This ATP demand is expected to be met by cyclic electron transport around photosystem I. Of the 2 cyclic electron transport pathways, PROTON GRADIENT REGULATION 5 (PGR5)/PGR5-like photosynthetic phenotype 1 (PGRL1)-dependent and chloroplast NADH dehydrogenase-like (NDH)-dependent, ATP is supplied primarily by the NDH-dependent pathway in NADP-malic enzyme-type C4 plants. However, the roles of these pathways in photoprotection of photosystem I have not been fully evaluated in C4 plants. In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines to investigate the redox state of the electron transport chain and high light sensitivity of photosystems. The double-knockdown line exhibited poorer growth than the FbNdhO-RNAi line, indicating that both pathways were essential for ATP production. The acceptor side of P700 was limited under high light conditions in the FbNdhO-RNAi line, while it was limited under lower to high light conditions in the FbPGRL1-RNAi and double-knockdown lines. Ferredoxin was reduced more in the FbPGRL1-RNAi line than in the wild type, and it was even more reduced in the double-knockdown line. Photoinhibition caused by high light exposure was more pronounced in photosystem I than in photosystem II in these lines. These results demonstrate that both cyclic electron transport pathways are essential not only for ATP production required for growth but also for protecting photosystem I from photoinhibition by alleviating the acceptor-side limitations of P700 in C4 plants.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by-nc-nd. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 9
Claim · model-written summary
The double-knockdown Flaveria bidentis line grows more poorly than the FbNdhO-RNAi line.
- Taxon
- Flaveria bidentis
_close-up_(13741736383).jpg?width=60)
Flaveria bidentise1 - Treatment
- double-knockdowne2
- Outcome
- growthe2
- Direction
- poorere2
- Qualifier
- indicating that both pathways were essential for ATP productione2
- Comparator
- FbNdhO-RNAi linee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_close-up_(13741736383).jpg?width=500)
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e2“The double-knockdown line exhibited poorer growth than the FbNdhO-RNAi line, indicating that both pathways were essential for ATP production”
Claim · model-written summary
Acceptor-side limitation of P700 under high light is found in the FbNdhO-RNAi line.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Material
- FbNdhO-RNAi linee3
- Treatment
- high light conditionse3
- Gene
- FbNdhOe3
- Outcome
- acceptor side of P700e3
- Direction
- limitede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e3“The acceptor side of P700 was limited under high light conditions in the FbNdhO-RNAi line, while it was limited under lower to high light conditions in the FbPGRL1-RNAi and double-knockdown lines”
Claim · model-written summary
Acceptor-side limitation of P700 under lower to high light is found in the FbPGRL1-RNAi line.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Material
- FbPGRL1-RNAie3
- Treatment
- lower to high light conditionse3
- Gene
- FbPGRL1e3
- Outcome
- acceptor side of P700e3
- Direction
- limitede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e3“The acceptor side of P700 was limited under high light conditions in the FbNdhO-RNAi line, while it was limited under lower to high light conditions in the FbPGRL1-RNAi and double-knockdown lines”
Claim · model-written summary
Acceptor-side limitation of P700 under lower to high light is found in the double-knockdown line.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Material
- double-knockdowne3
- Treatment
- lower to high light conditionse3
- Outcome
- acceptor side of P700e3
- Direction
- limitede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e3“The acceptor side of P700 was limited under high light conditions in the FbNdhO-RNAi line, while it was limited under lower to high light conditions in the FbPGRL1-RNAi and double-knockdown lines”
Claim · model-written summary
Ferredoxin is reduced more in the FbPGRL1-RNAi line than in the wild type.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Material
- FbPGRL1-RNAi linee4
- Treatment
- knockdown lines targeting PGRL1e1
- Outcome
- Ferredoxine4
- Direction
- reduced moree4
- Comparator
- wild typee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e4“Ferredoxin was reduced more in the FbPGRL1-RNAi line than in the wild type, and it was even more reduced in the double-knockdown line”
Claim · model-written summary
Ferredoxin is even more reduced in the double-knockdown line than in the FbPGRL1-RNAi line.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Material
- double-knockdown linee4
- Treatment
- double-knockdowne1
- Outcome
- Ferredoxine4
- Direction
- even more reducede4
- Comparator
- FbPGRL1-RNAi linee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e4“Ferredoxin was reduced more in the FbPGRL1-RNAi line than in the wild type, and it was even more reduced in the double-knockdown line”
Claim · model-written summary
Photoinhibition caused by high light is more pronounced in photosystem I than in photosystem II.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Treatment
- high light exposuree5
- Outcome
- Photoinhibitione5
- Direction
- more pronouncede5
- Qualifier
- in photosystem Ie5
- Comparator
- photosystem IIe5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e5“Photoinhibition caused by high light exposure was more pronounced in photosystem I than in photosystem II in these lines”
Claim · model-written summary
Both cyclic electron transport pathways protect photosystem I from photoinhibition by alleviating the acceptor-side limitations of P700.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Outcome
- protecting photosystem I from photoinhibitione6
- Qualifier
- alleviating the acceptor-side limitations of P700e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e6“These results demonstrate that both cyclic electron transport pathways are essential not only for ATP production required for growth but also for protecting photosystem I from photoinhibition by alleviating the acceptor-side limitations of P700 in C4 plants”
Claim · model-written summary
Both cyclic electron transport pathways are essential for ATP production required for growth.
- Taxon
- Flaveria bidentisFlaveria bidentise1
- Outcome
- growthe6
- Qualifier
- ATP production required for growthe6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In this study, we used Flaveria bidentis knockdown lines targeting PGRL1 or NdhO and their double-knockdown lines”
e6“These results demonstrate that both cyclic electron transport pathways are essential not only for ATP production required for growth but also for protecting photosystem I from photoinhibition by alleviating the acceptor-side limitations of P700 in C4 plants”