Developmentally regulated association of plastid division protein FtsZ1 to thylakoid membranes in Arabidopsis thaliana
Résumé
FtsZ is a key protein involved in bacterial and organellar division. Bacteria have only one ftsZ gene, while chlorophytes (higher plants and green alga) have two distinct FtsZ gene families, named FtsZ1 and FtsZ2. This raises the question why chloroplasts in these organisms need distinct FtsZ proteins to divide. In order to unravel new functions associated with FtsZ proteins, we have identified and characterized an Arabidopsis thaliana FtsZ1 loss-of-function mutant. ftsZ1 knockout mutants are impeded in chloroplast division and division is restored when FtsZ1 is expressed at low level. FtsZ1 overexpressing plants show a drastic inhibition in chloroplast division. Chloroplast morphology is altered in ftsZ1 with chloroplasts having abnormalities in the thylakoid membrane network. Overexpression of FtsZ1 also induced defects in thylakoid organization with an increased network of twisting thylakoids and larger grana. We show that FtsZ1, in addition to be present in the stroma, is tightly associated with the thylakoid fraction. This association is developmentally regulated since FtsZ1 is found in the thylakoid fraction of young developing plant leaves but not in mature and old plant leaves. Our results suggest that plastid division FtsZ1 may play a function during leaf development in thylakoid organization thus highlighting new functions for green plastid FtsZ.
Domaines
Sciences du Vivant [q-bio]
Origine : Fichiers produits par l'(les) auteur(s)
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