Journal Article

PreJuSER-14173

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Photosystem II fluorescence lifetime imaging in avocado leaves: Contributions of the lutein-epoxide and violaxanthin cycles to fluorescence quenching

Matsubara, S.FZJ* ; Chen, Y.-C. ; Caliandro, R.FZJ* ; Govindjee, G. ; Clegg, R. M.FZJ*

2011
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.jphotobiol.2011.01.003

Abstract: Lifetime-resolved imaging measurements of chlorophyll a fluorescence were made on leaves of avocado plants to study whether rapidly reversible ΔpH-dependent (transthylakoid H(+) concentration gradient) thermal energy dissipation (qE) and slowly reversible ΔpH-independent fluorescence quenching (qI) are modulated by lutein-epoxide and violaxanthin cycles operating in parallel. Under normal conditions (without inhibitors), analysis of the chlorophyll a fluorescence lifetime data revealed two major lifetime pools (1.5 and 0.5 ns) for photosystem II during the ΔpH build-up under illumination. Formation of the 0.5-ns pool upon illumination was correlated with dark-retention of antheraxanthin and photo-converted lutein in leaves. Interconversion between the 1.5- and 0.5-ns lifetime pools took place during the slow part of the chlorophyll a fluorescence transient: first from 1.5 ns to 0.5 ns in the P-to-S phase, then back from 0.5 ns to 1.5 ns in the S-to-M phase. When linear electron transport and the resulting ΔpH build-up were inhibited by treatment with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), the major fluorescence intensity was due to a 2.2-ns lifetime pool with a minor faster contribution of approximately 0.7 ns. In the presence of DCMU, neither the intensity nor the lifetimes of fluorescence were affected by antheraxanthin and photo-converted lutein. Thus, we conclude that both antheraxanthin and photo-converted lutein are able to enhance ΔpH-dependent qE processes that are associated with the 0.5-ns lifetime pool. However, unlike zeaxanthin, retention of antheraxanthin and photo-converted lutein may not by itself stabilize quenching or cause qI.

Keyword(s): Diuron: pharmacology (MeSH) ; Hydrogen-Ion Concentration (MeSH) ; Light (MeSH) ; Lutein: chemistry (MeSH) ; Microscopy, Fluorescence (MeSH) ; Persea: enzymology (MeSH) ; Photosystem II Protein Complex: chemistry (MeSH) ; Photosystem II Protein Complex: metabolism (MeSH) ; Plant Leaves: drug effects (MeSH) ; Plant Leaves: enzymology (MeSH) ; Time Factors (MeSH) ; Xanthophylls: chemistry (MeSH) ; Photosystem II Protein Complex ; Xanthophylls ; violaxanthin ; Lutein ; Diuron ; J ; Fluorescence lifetime imaging microscopy (auto) ; Lutein (auto) ; Lutein epoxide (auto) ; Polar plot (auto) ; Thermal energy dissipation (auto) ; Xanthophyll cycle (auto)

Note: The research stay of S.M. at University of Illinois at Urbana-Champaign was supported by a Deutsche Akademische Austauschdienst (DAAD) travel grant (PPP-USA, D/07/10566). Y.-C.C. was supported by the Taiwan Merit Scholarships (TMS-094-1-A-036). G. was supported by the Department of Plant Biology at the University of Illinois at Urbana-Champaign. We thank Kelly Gillespie and Lisa Ainsworth (Department of Plant Biology, University of Illinois at Urbana-Champaign) for their help in freeze-drying the leaf disc samples. R.M.C. thanks the Research Board at UIUC for support. Although data were not included in this work, friendly and expert assistance by Mayandi Sivaguru (Microscopy and Imaging Facility, Institute for Genomic Biology, University of Illinois at Urbana-Champaign) for spinning disc confocal microscopy experiments is greatly acknowledged.

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Contributing Institute(s):

1. Pflanzenwissenschaften (IBG-2)

Research Program(s):

1. Terrestrische Umwelt (P24)

Appears in the scientific report 2011

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