Remodeling of the major light-harvesting antenna protein of psii protects the young leaves of barley (Hordeum vulgare L.) from photoinhibition under prolonged iron deficiency

Akihiro Saito, Tomohisa Iino, Kintake Sonoike, Eitaro Miwa, Kyoko Higuchi

研究成果: Article査読

22 被引用数 (Scopus)

抄録

Because of the high demand for iron of the photosynthetic apparatus in thylakoid membranes, iron deficiency primarily affects the electron transfer between the two photosystems (PSI and PSII), resulting in photooxidative damage in plants. However, in barley, PSII is protected against photoinhibition, and the plant survives even with a low iron content in its chlorotic leaves. In this study, we report an adaptation mechanism of the photosynthetic apparatus in barley to iron deficiency, which is concomitant with the remodeling of a PSII antenna system. Transcriptome analysis revealed that long-term iron deficiency induced the expression of two genes of the major light-harvesting Chl a/b-binding protein of PSII (LHCII), namely HvLhcb1.11 and HvLhcb1.12 . Chl fluorescence analysis of the wild type and Lhcb1-less chlorina mutants clearly showed that non-photochemical quenching (NPQ) of the wild type was increased by approximately 200 % by iron deficiency, whereas NPQ of chlorina mutants did not change significantly under iron deficiency. The mutant showed severe photodamage in young leaves under prolonged iron deficiency, suggesting that the HvLhcb1 protein is essential for both thermal dissipation and photoprotection in iron-deficient barley. Analysis of thylakoid protein complexes revealed that the proportion of the monomeric form of Lhcb1 significantly increased in barley grown under iron-deficient conditions. We hypothesize that alteration of the HvLhcb1 subpopulations modifies the organization of LHCII in the thylakoid membranes, which is a key step for thermal dissipation to compensate for excess excitation energy and thereby protect the photosystems from serious damage in iron-deficient barley leaves.

本文言語English
ページ(範囲)2013-2030
ページ数18
ジャーナルPlant and Cell Physiology
51
12
DOI
出版ステータスPublished - 2010 12

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

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