Full text
| |
| Author(s): |
José Matheus Camargo Bonatto
Total Authors: 1
|
| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2010-03-31 |
| Examining board members: |
Carlos Alberto Labate;
Marcia Regina Braga;
Lazaro Eustaquio Pereira Peres
|
| Advisor: | Carlos Alberto Labate |
| Abstract | |
The light harvesting complex (LHC) of photosystem II (PSII) is the major ensemble of pigmet-biding proteins situated in the thylakoid membranes of the chloroplast in plants. The LHCbII functions as an energy-transferring antenna for capturing and delivering light energy to the photosystems PSII and PSI. The coordinated actions of the two photosystems in turn drive the flow of electrons, generated by the splitting of water, through the thylakoid membranes to produce the assimilatory force ATP and NADPH. The chemical energy produced by photosynthesis is very important for the assimilation of carbon, amino acids biosynthesis, and secundary metabolism. Therefore it is an important gene for biotechnological studies. Transgenic tobacco lines (TR-1 and TR-2) which express the pea Lhcb1*2 transgene constitutively obtained by Labate et al. (2004) were used in this work. These plants presented pleiotropic effects related to anatomy, morphology, biochemistry and physiology. As a protein may not act by itself, but it is, frequently interacting with other proteins, influencing a lot of metabolic processes. The proteomic profile of these transgenic lines, in relation to the wild type (WT), was investigated. The total proteins extracted from leaves of three-month old plants grown in growth chambers were separated by 2DPAGE. The differentially expressed proteins were identified by LC-MS/MS. The results showed that 225 spots displayed significant changes in the expression of the two transgenic lines in relation to the WT. 122 spots were exclusively expressed in the transgenic lines, and 24 only in the wild type. Many proteins as ATP synthase and ribulose bisphosphate carboxylase/oxygenase activase are overexpressed in the transgenic lines, but the glutamine synthetase, an important protein tor nitrogen recycling in the chloroplasts, showed a reducted level of expression. In order to analyse the alterations of the expression of genes related to the circadian rhythm among others, involved in the conformation of the PSII, cotyledons from etiolated seedlings were thenexposed to light and samples collected after 0, 3, 6, 12 and 24 hours. The level of transcripts were analysed by RT/RT-PCR. The PSII conformation were analysed by transmition electron microscopy, with the aim of verifying the evolution of plastids into the chloroplasts which could be leading to changes in plant development. The overexpression of the pea Lhcb1*2 gene in transgenic tobacco plants, lead to the induction and suppression of several proteins and genes in key metabolic pathways, as a way to establish a cellular homeostasis, exerting a significant influence on plant development and biomass production. (AU) | |
| FAPESP's process: | 08/03280-6 - Characterization of the leaf proteome of transgenic Nicotiana tabacum that constitutively express pea Lhcb1*2 gene |
| Grantee: | José Matheus Camargo Bonatto |
| Support Opportunities: | Scholarships in Brazil - Master |