A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Depletion of leaf-type ferredoxin-NADP plus oxidoreductase results in the permanent induction of photoprotective mechanisms in Arabidopsis chloroplasts
Tekijät: Lintala M, Lehtimäki N, Benz JP, Jungfer A, Soll J, Aro EM, Bölter B, Mulo P
Kustantaja: WILEY-BLACKWELL
Julkaisuvuosi: 2012
Journal: Plant Journal
Tietokannassa oleva lehden nimi: PLANT JOURNAL
Lehden akronyymi: PLANT J
Numero sarjassa: 5
Vuosikerta: 70
Numero: 5
Aloitussivu: 809
Lopetussivu: 817
Sivujen määrä: 9
ISSN: 0960-7412
DOI: https://doi.org/10.1111/j.1365-313X.2012.04930.x
Tiivistelmä
Arabidopsis thaliana contains two photosynthetically competent chloroplast-targeted ferredoxin-NADP+ oxidoreductase (FNR) isoforms that are largely redundant in their function. Nevertheless, the FNR isoforms also display distinct molecular phenotypes, as only the FNR1 is able to directly bind to the thylakoid membrane. We report the consequences of depletion of FNR in the F1 (fnr1 X fnr2) and F2 (fnr1 fnr2) generation plants of the fnr1 and fnr2 single mutant crossings. The fnr1 X fnr2 plants, with a decreased total content of FNR, showed a small and pale green phenotype, accompanied with a marked downregulation of photosynthetic pigment-protein complexes. Specifically, when compared with the wild type (WT), the quantum yield of photosystem II (PSII) electron transport was lower, non-photochemical quenching (NPQ) was higher and the rate of P700+ re-reduction was faster in the mutant plants. The slight over-reduction of the plastoquinone pool detected in the mutants resulted in the adjustment of the reactive oxygen species (ROS) scavenging systems, as both the content and de-epoxidation state of xanthophylls, as well as the content of a-tocopherol, were higher in the leaves of the mutant plants when compared with the WT. The fnr1 fnr2 double mutant plants, which had no detectable FNR and possessed an extremely downregulated photosynthetic machinery, survived only when grown heterotrophically in the presence of sucrose. Intriguingly, the fnr1 fnr2 plants were still capable of sustaining the biogenesis of a few malformed chloroplasts.
Arabidopsis thaliana contains two photosynthetically competent chloroplast-targeted ferredoxin-NADP+ oxidoreductase (FNR) isoforms that are largely redundant in their function. Nevertheless, the FNR isoforms also display distinct molecular phenotypes, as only the FNR1 is able to directly bind to the thylakoid membrane. We report the consequences of depletion of FNR in the F1 (fnr1 X fnr2) and F2 (fnr1 fnr2) generation plants of the fnr1 and fnr2 single mutant crossings. The fnr1 X fnr2 plants, with a decreased total content of FNR, showed a small and pale green phenotype, accompanied with a marked downregulation of photosynthetic pigment-protein complexes. Specifically, when compared with the wild type (WT), the quantum yield of photosystem II (PSII) electron transport was lower, non-photochemical quenching (NPQ) was higher and the rate of P700+ re-reduction was faster in the mutant plants. The slight over-reduction of the plastoquinone pool detected in the mutants resulted in the adjustment of the reactive oxygen species (ROS) scavenging systems, as both the content and de-epoxidation state of xanthophylls, as well as the content of a-tocopherol, were higher in the leaves of the mutant plants when compared with the WT. The fnr1 fnr2 double mutant plants, which had no detectable FNR and possessed an extremely downregulated photosynthetic machinery, survived only when grown heterotrophically in the presence of sucrose. Intriguingly, the fnr1 fnr2 plants were still capable of sustaining the biogenesis of a few malformed chloroplasts.
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