Chromoplast differentiation: current status and perspectives.
Chromoplasts are carotenoid-accumulating plastids conferring color to many flowers and fruits as well as to some tubers and roots. Chromoplast differentiation proceeds from preexisting plastids, most often chloroplasts. One of the most prominent changes is remodeling of the internal membrane system associated with the formation of carotenoid-accumulating structures. During the differentiation process the plastid genome is essentially stable and transcriptional activity is restricted. The buildup of the chromoplast for specific metabolic characteristics is essentially dependent upon the transcriptional activity of the nucleus. Important progress has been made in terms of mediation of the chloroplast-to-chromoplast transition with the discovery of the crucial role of the Or gene. In this article we review recent developments in the structural, biochemical and molecular aspects of chromoplast differentiation and also consider the reverse differentiation of chromoplasts into chloroplast-like structures during the regreening process occurring in some fruit. Future perspectives toward a full understanding of chromoplast differentiation include in-depth knowledge of the changes occurring in the plastidial proteome during chromoplastogenesis, elucidation of the role of hormones and the search for signals that govern the dialog between the nuclear and the chromoplastic genome.
Egea
Isabel
I
Université de Toulouse, INP-ENSA Toulouse, Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole BP 32607, Castanet-Tolosan F-31326, France.
Barsan
Cristina
C
Bian
Wanping
W
Purgatto
Eduardo
E
Latché
Alain
A
Chervin
Christian
C
Bouzayen
Mondher
M
Pech
Jean-Claude
JC
D002338:Carotenoids / Q000096:biosynthesis; D002736:Chloroplasts / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D010940:Plant Proteins / Q000378:metabolism; D010944:Plants / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D018087:Plastids / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
D010940:Plant Proteins; D002338:Carotenoids