Characteristics of the tomato chromoplast revealed by proteomic analysis.
Chromoplasts are non-photosynthetic specialized plastids that are important in ripening tomato fruit (Solanum lycopersicum) since, among other functions, they are the site of accumulation of coloured compounds. Analysis of the proteome of red fruit chromoplasts revealed the presence of 988 proteins corresponding to 802 Arabidopsis unigenes, among which 209 had not been listed so far in plastidial databanks. These data revealed several features of the chromoplast. Proteins of lipid metabolism and trafficking were well represented, including all the proteins of the lipoxygenase pathway required for the synthesis of lipid-derived aroma volatiles. Proteins involved in starch synthesis co-existed with several starch-degrading proteins and starch excess proteins. Chromoplasts lacked proteins of the chlorophyll biosynthesis branch and contained proteins involved in chlorophyll degradation. None of the proteins involved in the thylakoid transport machinery were discovered. Surprisingly, chromoplasts contain the entire set of Calvin cycle proteins including Rubisco, as well as the oxidative pentose phosphate pathway (OxPPP). The present proteomic analysis, combined with available physiological data, provides new insights into the metabolic characteristics of the tomato chromoplast and enriches our knowledge of non-photosynthetic plastids.
Barsan
Cristina
C
Université de Toulouse, INP-ENSA Toulouse, Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole BP 32607, F-31326 Castanet-Tolosan, France.
Sanchez-Bel
Paloma
P
Rombaldi
Cesar
C
Egea
Isabel
I
Rossignol
Michel
M
Kuntz
Marcel
M
Zouine
Mohamed
M
Latché
Alain
A
Bouzayen
Mondher
M
Pech
Jean-Claude
JC
D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013058:Mass Spectrometry; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018087:Plastids / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D040901:Proteomics
D010940:Plant Proteins