Book with abstracts from the COST Action 0905 meeting in ... - UMB

PCP1 AND ATOSA1: PROTEINS INVOLVED IN CHLOROPLAST
IRON HOMEOSTASIS IN ARABIDOPSIS.
Anna Manara, Giovanni Dal Corso, Antonella Furini
Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona
(Italy)
Keywords: Activity-of-bc1-complex family, chloroplast, Fe
This work is aimed at investigating the involvement in metal homeostasis of two
Arabidopsis thaliana proteins belonging to the Activity-of-bc 1 -complex family.
The first, PCP1, is homologous to a Brassica juncea gene modulated upon cadmium
treatment; the second, AtOSA1, is a stress-related protein involved in plant response to
oxidative stress. With the exception of a pale-green phenotype and a reduced total
chlorophyll content in atosa1 and atosa1/pcp1 mutants, knock-out plants do not show any
morphological/developmental abnormalities under standard conditions. Lack of PCP1 and
AtOSA1 have no effects on photosynthetic performances, even though both are localised
in chloroplasts. No differences in PSI and PSII protein composition were observed in
mutants, with the exception of a reduction of Fe-containing Rieske and Cyt f proteins.
These differences suggest that mutant plants could be impaired in homeostasis of metal
ions integrated into the photosynthetic apparatus. Indeed, mutant plants present a decrease
in thylakoid Fe content in comparison to WT and showed a reduced growth and
pronounced leaf chlorosis when cultured under Fe deficiency. Conversely, plants
overexpressing PCP1 or AtOSA1 have an increased Fe content in thylakoids. In WT plants
the expression of both genes is reduced by Fe deficiency. These data indicate a possible
involvement of PCP1 and AtOSA1 proteins in chloroplast Fe homeostasis.