Abstract
Sugarcane is an important crop for Brazilian economy both for its use in sugar and biofuels production, being Brazil the world´s leading producer of this culture. The growing need to reduce greenhouse gases in the atmosphere increased dramatically the appeal and demand for biofuels. Research indicates the exponential increase in bioethanol production in the upcoming years just exploring the residual biomass of plants. This bagasse left over from the process of production of sugar and ethanol is rich in carbon chains, mainly cellulose. Improvement of the way of providing that carbon for yeast is the challenge right now. Also, one of the main challenges is to derange the cell wall eliminating the most of the lignin, the main molecule that hampers the fermentation process. Thus, to understand how the lignin biosynthetic pathway occurs in the sugarcane stalk cell wall will help to comprehend the modulation of their genes and future handling of deposited monolignol levels, resulting in phenotypes with lower lignin content. The proteomic approach in this context is of great importance since most of the plant studies has a transcriptional focus. Correlate genomic/transcriptomic data with proteins that are actually expressed in stalk cells, contribute to a broader view of the lignification process of the cell wall in sugarcane. Therefore, the objective is from the perspective of proteomics, investigate the control of the formation of lignin in stalks of sugarcane using the environmental stresses as the main modulators in the formation and polymerization of the lignin. Experiments already conducted in the associated project to this proposal, using luxurious nitrogen fertilization and drought stress revealed nearly to 2,000 non-redundant proteins from diverse functional categories. Particularly, drought stress demonstrated to be more efficient in the modulation of lignin biosynthesis, changing protein abundance of enzymes involved in phenylpropanoid, aminoacid and carbon metabolism. As the main objective is to understand lignin regulation, we intend to identify transcription factors involved in lignin biosynthesis and polymerization. For this, we propose in this project the isolation of nuclear proteins in order to identify and absolute quantify the expression of transcription factors related to the lignin biosynthetic pathway. Thus, applying a targeted proteomics workflow, we are going to be able to monitor specific transcription factors. Accurate and precise quantification of these proteins are essential to understand changes in lignin content and composition during sugarcane maturation or environmental stress exposure. The international collaboration of this proposal came out due to its great contribution for the development of this project. Nuclei isolation from sugarcane stalks for proteomics application is handling tricky and targeted proteomics workflow requires very experienced people. These difficulties faced here in Brazil, can be circumvented by the collaboration with Dr. David Muddiman team who has confirmed experience in the field. (AU)
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