Genetic decrease in fatty acid unsaturation of phosphatidylglycerol increased photoinhibition of photosystem I at low temperature in tobacco leaves

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• 作者：A.G. Ivanov^a ; ^d ; ^{aivanov@uwo.ca} ; S.I. Allakhverdiev^b ; ^c ; ^d ; N.P.A. Huner^a ; N. Murata^d
• 关键词：PSI ; photosystem I ; PSII ; photosystem II ; P700 ; reaction center pigment of PSI ; P700+ ; oxidized form of the reaction center pigment of PSI ; PG ; phosphatidylglycerol
• 刊名：Biochimica et Biophysica Acta (BBA)/Bioenergetics
• 出版年：2012
• 期刊代码：13_00052728
• 类别：bio
• 出版时间：August, 2012
• 卷：1817
• 期：8
• 页码：1374-1379
• 文件大小：481 K

摘要

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.