Mutants, overexpressors and interactors of Arabidopsis plastocyanin isoforms: revised roles of plastocyanin in photosynthetic electron flow and thylakoid redox state
Articolo
Data di Pubblicazione:
2009
Citazione:
Mutants, overexpressors and interactors of Arabidopsis plastocyanin isoforms: revised roles of plastocyanin in photosynthetic electron flow and thylakoid redox state / P. Pesaresi, M. Schrfenberg, M. Weigel, I. Granlund, W.P. Schröder, G. Finazzi, F. Rappaport, S. Masiero, A. Furini, P. Jahns, D. Leister. - In: MOLECULAR PLANT. - ISSN 1674-2052. - 2:2(2009 Mar), pp. 236-248.
Abstract:
Two homologous plastocyanin isoforms are encoded by the genes PETE1 and PETE2 in the nuclear genome of
Arabidopsis thaliana. The PETE2 transcript is expressed at considerably higher levels and the PETE2 protein is the more
abundant isoform. Null mutations in the PETE genes resulted in plants, designated pete1 and pete2, with decreased plastocyanin
contents. However, despite reducing plastocyanin levels by over ;90%, a pete2 null mutation on its own affects
rates of photosynthesis and growth only slightly, whereas pete1 knockout plants, with about 60–80% of the wild-type
plastocyanin level, did not show any alteration. Hence, plastocyanin concentration is not limiting for photosynthetic electron
flow under optimal growth conditions, perhaps implying other possible physiological roles for the protein. Indeed,
plastocyanin has been proposed previously to cooperate with cytochrome c6A (Cyt c6A) in thylakoid redox reactions, but we
find no evidence for a physical interaction between the two proteins, using interaction assays in yeast. We observed
homodimerization of Cyt c6A in yeast interaction assays, but also Cyt c6A homodimers failed to interact with plastocyanin.
Moreover, phenotypic analysis of atc6-1 pete1 and atc6-1 pete2 double mutants, each lacking Cyt c6A and one of the two
plastocyanin-encoding genes, failed to reveal any genetic interaction. Overexpression of either PETE1 or PETE2 in the pete1
pete2 double knockout mutant background results in essentially wild-type photosynthetic performance, excluding
the possibility that the two plastocyanin isoforms could have distinct functions in thylakoid electron flow.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
P. Pesaresi, M. Schrfenberg, M. Weigel, I. Granlund, W.P. Schröder, G. Finazzi, F. Rappaport, S. Masiero, A. Furini, P. Jahns, D. Leister
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