Genetic decrease in fatty acid unsaturation of phosphatidylglycerol increased photoinhibition of photosystem I at low temperature in tobacco leaves.
Biochim Biophys Acta
; 1817(8): 1374-9, 2012 Aug.
Article
em En
| MEDLINE
| ID: mdl-22445720
ABSTRACT
Leaves of transgenic tobacco plants with decreased levels of fatty acid unsaturation in phosphatidylglycerol (PG) exhibited a slightly lower level of the steady state oxidation of the photosystem I (PSI) reaction center P700 (P700(+)) than wild-type plants. The PSI photochemistry of wild-type plants was only marginally affected by high light treatments. Surprisingly, all plants of transgenic lines exhibited much higher susceptibility to photoinhibition of PSI than wild-type plants. This was accompanied by a 2.5-fold faster re-reduction rate of P700(+) in the dark, indicating a higher capacity for cyclic electron flow around PSI in high light treated transgenic leaves. This was associated with a much higher intersystem electron pool size suggesting over-reduction of the PQ pool in tobacco transgenic lines with altered PG unsaturation compared to wild-type plants. The physiological role of PG unsaturation in PSI down-regulation and modulation of the capacity of PSI-dependent cyclic electron flows and distribution of excitation light energy in tobacco plants under photoinhibitory conditions at low temperatures is discussed. This article is part of a Special Issue entitled Photosynthesis Research for Sustainability from Natural to Artificial.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fosfatidilgliceróis
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Nicotiana
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Complexo de Proteína do Fotossistema I
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Ácidos Graxos Insaturados
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article