Stalk and nuclear proteomes of sugarcane (Saccharum spp.) associated to the control of lignin biosynthesis

Abstract

Sugarcane is an important crop for the national economy, both for its use in the production of sugar as in biofuels production and Brazil is the world's leading producer of this crop. The growing need to reduce greenhouse gases in the atmosphere expanded the appeal and demand for biofuels dramatically. Surveys show the exponential increase in bioethanol production in the next 14 years just exploring the residual biomass plants. The residue left over from the process of production of sugar and alcohol is rich in carbon chains, especially cellulose. The improvement of the availability of this form of carbon for yeasts is the challenge right now. Physical and chemical processes seek to separate the glucose from the cell wall residue. Another challenge is to derange the cell wall eliminating the most of the lignin, which is the main molecule that hinders the fermentation process. Thus, understanding how the biosynthesis of lignin occurs in the cell wall of stems of sugarcane will help in understanding the modulation of genes and will permit in the future the manipulation of monolignols levels deposited, resulting in phenotypes with lower lignin content. A proteomic approach in this context is of great importance since most studies have focused on transcriptional level. The correlation of what is known in the literature about the genes involved in the lignin pathway with proteins actually expressed in stem cells contribute to a broader view of the processes involved in cell wall lignification in sugarcane. Therefore, the aim of this work is from the perspective of proteomics to investigate the control of lignin formation in stalks of sugarcane cultivars with contrasting lignin content, using different environments like drought and nitrogen fertilization as the main regulators of the formation and polymerization of lignin. Nuclear proteins will also be isolated in order to characterize the differences between the contrasting genotypes mainly for the expression of transcription factors related to the lignin biosynthesis. (AU)