Impact of ScEPG I (endopolygalacturonase I) overexpression and silencing on cell wall composition in Saccharum spp.: Anatomical, biochemical and molecular studies.

Abstract

Sugarcane bagasse is a promising raw material for the production of second-generation ethanol, but its use presents challenges, from the high costs of pre-treatment and hydrolysis, associated with cell wall recalcitrance, which limits the saccharification yield. Although pectins have been largely neglected as important components of the cell wall, due to their low content (~8%) in sugarcane, they confer recalcitrance as they are responsible for cell adhesion and porosity, limiting the traffic of glycosyl hydrolases that would facilitate the subsequent steps of hydrolysis of the other polysaccharides. One of the efficient endogenous cell wall degradation processes is the formation of lysigenous aerenchyma that occurs in sugarcane roots and preliminary studies suggest further research into key aspects of the initial mechanisms (loss of adhesion, increase in porosity and wall loosening). ) of this process to target bioenergy, from the search and selection of orthologous pectinase genes to be used in the development of sugarcane genotypes, presenting biomass with reduced recalcitrance using genetic engineering, aiming to increase the production of ethanol. In this sense, the objective of this project is to evaluate the effect of overexpression and silencing of ScEPG I (endopolygalacturonase) on aerenchyma formation in roots, as well as on the composition and cell wall dynamics of sugarcane stalks. To achieve this goal, several tools or strategies will be used: isolation and cloning of sequences, design of genetic constructions for genetic modification, production of transgenic strains, transcript expression profile and enzymatic activity of glycosyl hydrolases, biochemical and anatomical characterization of the different polymers of the cell wall, saccharification yield, among others. The project will bring new information about the role of ScEPG I in pectin degradation and its specific impact during aerenchyma formation, emphasizing the opportunities and challenges of using ScEPG I, as a genetic engineering tool, to alter the cell wall of stems. , main sources of lignocellulosic biomass in sugarcane, aiming to help boost traditional practices of genetic improvement and biotechnological approaches for the development of second-generation ethanol. (AU)