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Photoinhibition of photosystem I in a pea mutant with altered LHCII organization

Paper ID Volume ID Publish Year Pages File Format Full-Text
29661 44427 2015 12 PDF Available
Title
Photoinhibition of photosystem I in a pea mutant with altered LHCII organization
Abstract

•The pea mutant Costata 2/133 exhibits decreased abundance of PSI complexes.•The pea mutant Costata 2/133 exhibits a limited capacity for state transitions.•Oligomerization of LHCII affects the susceptibility of PSI to high light stress.

Comparative analysis of in vivo chlorophyll fluorescence imaging revealed that photosystem II (PSII) photochemical efficiency (Fv/Fm) of leaves of the Costata 2/133 pea mutant with altered pigment composition and decreased level of oligomerization of the light harvesting chlorophyll a/b-protein complexes (LHCII) of PSII (Dobrikova et al., 2000; Ivanov et al., 2005) did not differ from that of WT. In contrast, photosystem I (PSI) activity of the Costata 2/133 mutant measured by the far-red (FR) light inducible P700 (P700+) signal exhibited 39% lower steady state level of P700+, a 2.2-fold higher intersystem electron pool size (e−/P700) and higher rate of P700+ re-reduction, which indicate an increased capacity for PSI cyclic electron transfer (CET) in the Costata 2/133 mutant than WT. The mutant also exhibited a limited capacity for state transitions. The lower level of oxidizable P700 (P700+) is consistent with a lower amount of PSI related chlorophyll protein complexes and lower abundance of the PsaA/PsaB heterodimer, PsaD and Lhca1 polypeptides in Costata 2/133 mutant. Exposure of WT and the Costata 2/133 mutant to high light stress resulted in a comparable photoinhibition of PSII measured in vivo, although the decrease of Fv/Fm was modestly higher in the mutant plants. However, under the same photoinhibitory conditions PSI photochemistry (P700+) measured as ΔA820−860 was inhibited to a greater extent (50%) in the Costata 2/133 mutant than in the WT (22%). This was accompanied by a 50% faster re-reduction rate of P700+ in the dark indicating a higher capacity for CET around PSI in high light treated mutant leaves. The role of chloroplast thylakoid organization on the stability of the PSI complex and its susceptibility to high light stress is discussed.

Keywords
AG, afterglow thermoluminescence band; DCMU, 3-(3,4-dichlorophenyl)-1,1-dimethylurea; DCPIP, 2,6-dichlorophenolindophenol; Fv/Fm, maximum photochemical efficiency of PSII in the dark adapted state; Fr, capacity for state transitions; LHCII a/b, light-harv
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Photoinhibition of photosystem I in a pea mutant with altered LHCII organization
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 152, Part B, November 2015, Pages 335–346
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us