Characterization of cell wall architecture in Setaria viridis overexpressing genes from glicosyltransferase 61 family

• Grant number: 24/08691-7
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: March 01, 2025
• End date: February 28, 2026
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal Investigator: Wagner Rodrigo de Souza
• Grantee: Tamiris Machado Kobayasi
• Supervisor: Paul Dupree
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Institution abroad: University of Cambridge, England
• Associated to the scholarship: 23/05780-6 - Overexpression of xylan arabinosyltransferase genes to improve biomass digestibility in Setaria viridis, BP.DD

Abstract

Currently, the use of lignocellulosic biomass for production of liquid biofuels is seen as a strategy with great potential for reducing dependence on carbon-based fuels. However, the biomass cell wall is composed of a complex network of polymers that hinder enzymatic access to fermentable sugars, inhibiting cellulose digestion and becoming a major obstacle to ethanol production. To overcome this obstacle, physical and chemical treatments are necessary to degrade the lignocellulosic macromolecules, which ends up increasing production costs. Therefore, genetic modification of the cell wall with the aim of altering its composition, emerges as a promising alternative for reducing recalcitrance and increasing performance in ethanol production processes. In the present study so far, we have established a strategy for genetic alteration of the cell wall, aiming to reduce recalcitrance and consequently increase biomass digestibility. The model plant Setaria viridis was selected as the object of study because it is a grass phylogenetically related to sugar cane. Through genetic transformation techniques, two genes from the xylan arabinosyltransferase (XAT) family are being overexpressed, SvXAT2 and SvXAT3. These enzymes are responsible for the incorporation of arabinose residues on the side chains of the hemicellulosic portion of the cell wall called glucuronoarabinoxylan (GAX). It is speculated that increasing the levels of these residues may reduce the crystallinity index and the degree of polymerization of the cell wall, resulting in increased biomass digestibility.