Petrizzo, Rocco , Boronat, Alberto .
A New Insight Into the Tomato Chromoplast Proteome using DIGE.
Tomato fruit is composed of elongated tomato cells filled with organelles called chromoplasts. Chromoplasts are found in coloured organs of plants such as fruit and floral petals, to which they give their distinctive colours. The main characteristic of ripening is the dramatic increase in the carotenoids content of the fruit, mainly lycopene in membrane-bound crystals within the plastids, and the disappearance of chlorophyll. Moreover, the chloroplast-chromoplast transition is marked by the degradation of the highly structured thylakoid membrane system, and a reduction in the levels of proteins and mRNAs associated with photosynthesis. To evaluate the metabolic role of chromoplasts during fruit ripening we have undertaken a proteomic study of this organelle. Intact chromoplast of wild-type and transgenic plants were isolated using sucrose density-gradient centrifugation. We report about a comparative proteomics approach (2D-DIGE) to identify specific proteins related with carotenoides accumulation. Proteins were labelled with CyDyes DIGE® fluorochromes (GE Healthcare). First dimension was carried out on 24cm pre-cast IPG strips with a pH gradient of 3-11NL. 2-DE was performed using the Ettan DALTsix system. Analysis has been done using the Decyder software® (GE Healthcare). Our preliminary results show clear differences between tomato chromoplasts from wt and transgenic lines. A number of spots displaying at least 2-fold changes in relative abundance were chosen for identification. Spots were excised from 2-DE gels, tryptically digested and analysed by MALDI-TOF/TOF MS or ESI-Q-TOF MS. Acquired spectra were then searched with Mascot (Matrix Science, UK) against the NCBI database and blasted against the Tomato EST database. The identified proteins can be classified in the following groups: 1) metabolism; 2) ionic channels, ion transporter and related; 3) defence/repair; 4) miscellaneous; 5) Unknown; 6) Not identified.
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1 - University of Barcelona, Biochemistry and Molecular Biology, Avda. Diagonal 645, Faculty of Biology, New Building, Barcelona, 08028, Spain
2 - University of Barcelona, Biochemistry and Molecular Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM