title: Chloroplast to chromoplast transition in tomato fruit: spectral confocal microscopy analyses of carotenoids and chlorophylls in isolated plastids and time-lapse recording on intact live tissue.
abstract: OBJECTIVE
  There are several studies suggesting that tomato (Solanum lycopersicum) chromoplasts arise from chloroplasts, but there is still no report showing the fluorescence of both chlorophylls and carotenoids in an intermediate plastid, and no video showing this transition phase.
  
  
  METHODS
  Pigment fluorescence within individual plastids, isolated from tomato fruit using sucrose gradients, was observed at different ripening stages, and an in situ real-time recording of pigment fluorescence was performed on live tomato fruit slices.
  
  
  RESULTS
  At the mature green and red stages, homogenous fractions of chloroplasts and chromoplasts were obtained, respectively. At the breaker stage, spectral confocal microscopy showed that intermediate plastids contained both chlorophylls and carotenoids. Furthermore, an in situ real-time recording (a) showed that the chloroplast to chromoplast transition was synchronous for all plastids of a single cell; and (b) confirmed that all chromoplasts derived from pre-existing chloroplasts.
  
  
  CONCLUSIONS
  These results give details of the early steps of tomato chromoplast biogenesis from chloroplasts, with the formation of intermediate plastids containing both carotenoids and chlorophylls. They provide information at the sub-cellular level on the synchronism of plastid transition and pigment changes.
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, BP 32607, Castanet-Tolosan, F-31326, France.
authors.forename: Isabel
authors.initials: I
authors.lastname: Egea
authors.forename: Wanping
authors.initials: W
authors.lastname: Bian
authors.forename: Cristina
authors.initials: C
authors.lastname: Barsan
authors.forename: Alain
authors.initials: A
authors.lastname: Jauneau
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Pech
authors.forename: Alain
authors.initials: A
authors.lastname: Latché
authors.forename: Zhengguo
authors.initials: Z
authors.lastname: Li
authors.forename: Christian
authors.initials: C
authors.lastname: Chervin
mesh_terms: D002338:Carotenoids / Q000096:biosynthesis*; D002734:Chlorophyll / Q000096:biosynthesis*; D002736:Chloroplasts / Q000378:metabolism*; D005638:Fruit / Q000737:chemistry / Q000166:cytology; D018551:Solanum lycopersicum / Q000378:metabolism; D018613:Microscopy, Confocal / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D018087:Plastids / Q000378:metabolism*
chemical_list: D002734:Chlorophyll; D002338:Carotenoids