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The chloroplast Ndh complex mediates the dark reduction of the plastoquinone pool in response to heat stress in tobacco leaves
Author(s) -
Sazanov Leonid A,
Burrows Paul A,
Nixon Peter J
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00573-0
Subject(s) - plastoquinone , thylakoid , chloroplast , electron transport chain , biophysics , chemistry , electron transfer , photochemistry , biology , biochemistry , gene
We have examined the effects of heat stress on electron transfer in the thylakoid membrane of an engineered plastid ndh deletion mutant, Δ1, incapable of performing the Ndh‐mediated reduction of the plastoquinone pool in the chloroplast. Upon heat stress in the dark, the rate of PSII‐independent reduction of PSI after subsequent illumination by far‐red light is dramatically enhanced in both Δ1 and a wild‐type control plant (WT). In contrast, in the dark, only the WT shows an increase in the reduction state of the plastoquinone pool. We conclude that the heat stress‐induced reduction of the intersystem electron transport chain can be mediated by Ndh‐independent pathways in the light but that in the dark the dominant pathway for reduction of the plastoquinone pool is catalysed by the Ndh complex. Our results therefore demonstrate a functional role for the Ndh complex in the dark.