Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum
Iron is a cofactor of photosystems and electron carriers in the photosynthetic electron transport chain. Low concentrations of dissolved iron are, therefore, the predominant factor that limits the growth of phototrophs in large parts of the open sea like the Southern Ocean and the North Pacific, res...
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ftdoajarticles:oai:doaj.org/article:2eff1ffdbf4849958a714866cec0f850 2023-05-15T18:25:48+02:00 Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum Jochen M. Buck Marie Wünsch Alexander F. Schober Peter G. Kroth Bernard Lepetit 2022-03-01T00:00:00Z https://doi.org/10.3389/fpls.2022.841058 https://doaj.org/article/2eff1ffdbf4849958a714866cec0f850 EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/fpls.2022.841058/full https://doaj.org/toc/1664-462X 1664-462X doi:10.3389/fpls.2022.841058 https://doaj.org/article/2eff1ffdbf4849958a714866cec0f850 Frontiers in Plant Science, Vol 13 (2022) diatoms Phaeodactylum tricornutum iron NPQ photoprotection Lhcx Plant culture SB1-1110 article 2022 ftdoajarticles https://doi.org/10.3389/fpls.2022.841058 2022-12-31T01:53:28Z Iron is a cofactor of photosystems and electron carriers in the photosynthetic electron transport chain. Low concentrations of dissolved iron are, therefore, the predominant factor that limits the growth of phototrophs in large parts of the open sea like the Southern Ocean and the North Pacific, resulting in “high nutrient–low chlorophyll” (HNLC) areas. Diatoms are among the most abundant microalgae in HNLC zones. Besides efficient iron uptake mechanisms, efficient photoprotection might be one of the key traits enabling them to outcompete other algae in HNLC regions. In diatoms, Lhcx proteins play a crucial role in one of the main photoprotective mechanisms, the energy-dependent fluorescence quenching (qE). The expression of Lhcx proteins is strongly influenced by various environmental triggers. We show that Lhcx2 responds specifically and in a very sensitive manner to iron limitation in the diatom Phaeodactylum tricornutum on the same timescale as the known iron-regulated genes ISIP1 and CCHH11. By comparing Lhcx2 knockout lines with wild type cells, we reveal that a strongly increased qE under iron limitation is based on the upregulation of Lhcx2. Other observed iron acclimation phenotypes in P. tricornutum include a massively reduced chlorophyll a content/cell, a changed ratio of light harvesting and photoprotective pigments per chlorophyll a, a decreased amount of photosystem II and photosystem I cores, an increased functional photosystem II absorption cross section, and decoupled antenna complexes. H2O2 formation at photosystem I induced by high light is lowered in iron-limited cells, while the amount of total reactive oxygen species is rather increased. Our data indicate a possible reduction in singlet oxygen by Lhcx2-based qE, while the other iron acclimation phenotype parameters monitored are not affected by the amount of Lhcx2 and qE. Article in Journal/Newspaper Southern Ocean Directory of Open Access Journals: DOAJ Articles Pacific Southern Ocean Frontiers in Plant Science 13 |
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Directory of Open Access Journals: DOAJ Articles |
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language |
English |
topic |
diatoms Phaeodactylum tricornutum iron NPQ photoprotection Lhcx Plant culture SB1-1110 |
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diatoms Phaeodactylum tricornutum iron NPQ photoprotection Lhcx Plant culture SB1-1110 Jochen M. Buck Marie Wünsch Alexander F. Schober Peter G. Kroth Bernard Lepetit Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum |
topic_facet |
diatoms Phaeodactylum tricornutum iron NPQ photoprotection Lhcx Plant culture SB1-1110 |
description |
Iron is a cofactor of photosystems and electron carriers in the photosynthetic electron transport chain. Low concentrations of dissolved iron are, therefore, the predominant factor that limits the growth of phototrophs in large parts of the open sea like the Southern Ocean and the North Pacific, resulting in “high nutrient–low chlorophyll” (HNLC) areas. Diatoms are among the most abundant microalgae in HNLC zones. Besides efficient iron uptake mechanisms, efficient photoprotection might be one of the key traits enabling them to outcompete other algae in HNLC regions. In diatoms, Lhcx proteins play a crucial role in one of the main photoprotective mechanisms, the energy-dependent fluorescence quenching (qE). The expression of Lhcx proteins is strongly influenced by various environmental triggers. We show that Lhcx2 responds specifically and in a very sensitive manner to iron limitation in the diatom Phaeodactylum tricornutum on the same timescale as the known iron-regulated genes ISIP1 and CCHH11. By comparing Lhcx2 knockout lines with wild type cells, we reveal that a strongly increased qE under iron limitation is based on the upregulation of Lhcx2. Other observed iron acclimation phenotypes in P. tricornutum include a massively reduced chlorophyll a content/cell, a changed ratio of light harvesting and photoprotective pigments per chlorophyll a, a decreased amount of photosystem II and photosystem I cores, an increased functional photosystem II absorption cross section, and decoupled antenna complexes. H2O2 formation at photosystem I induced by high light is lowered in iron-limited cells, while the amount of total reactive oxygen species is rather increased. Our data indicate a possible reduction in singlet oxygen by Lhcx2-based qE, while the other iron acclimation phenotype parameters monitored are not affected by the amount of Lhcx2 and qE. |
format |
Article in Journal/Newspaper |
author |
Jochen M. Buck Marie Wünsch Alexander F. Schober Peter G. Kroth Bernard Lepetit |
author_facet |
Jochen M. Buck Marie Wünsch Alexander F. Schober Peter G. Kroth Bernard Lepetit |
author_sort |
Jochen M. Buck |
title |
Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum |
title_short |
Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum |
title_full |
Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum |
title_fullStr |
Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum |
title_full_unstemmed |
Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum |
title_sort |
impact of lhcx2 on acclimation to low iron conditions in the diatom phaeodactylum tricornutum |
publisher |
Frontiers Media S.A. |
publishDate |
2022 |
url |
https://doi.org/10.3389/fpls.2022.841058 https://doaj.org/article/2eff1ffdbf4849958a714866cec0f850 |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Frontiers in Plant Science, Vol 13 (2022) |
op_relation |
https://www.frontiersin.org/articles/10.3389/fpls.2022.841058/full https://doaj.org/toc/1664-462X 1664-462X doi:10.3389/fpls.2022.841058 https://doaj.org/article/2eff1ffdbf4849958a714866cec0f850 |
op_doi |
https://doi.org/10.3389/fpls.2022.841058 |
container_title |
Frontiers in Plant Science |
container_volume |
13 |
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1766207461717442560 |