Identification and characterization of transcriptional factors that regulate the biosynthesis of lignin species Saccharum

• Grant number: 18/25058-5
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): March 01, 2019
• Effective date (End): October 31, 2020
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal researcher: Paulo Mazzafera
• Grantee: Juan Pablo Portilla Llerena
• Home Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The hybrids of sugarcane (Saccharum spp.) Currently grown are highly efficient at converting solar energy into assimilates, accumulating up to 18% sucrose in culms. The culture is primarily used for producing sugar and ethanol, generating as a waste bagasse, this biomass consists of cellulose (39%), hemicellulose (25%) and lignin (23%), has been used for the generation of ethanol second generation (E2G). More recently we have given attention to the development of sugarcane energy for the production of biomass for the production of E2G. The species used for this purpose is Saccharum spontaneum, with higher fiber content and a lower content of sucrose. The bagasse has a broad potential for producing E2G, however conversion to ethanol presents various challenges, the main one being the presence of lignin, which adversely affects the saccharification. The study of biosynthesis and deposition of lignin in plant cell wall is a major focus of research in the biofuels area. Genetic changes in lignin content and composition depend on the enzyme's position in the biosynthetic pathway and the gene expression profile involved in lignification. Another more recent approach to reducing or altering the composition of lignin is the manipulation of the regulators (transcription factors) in the expression of the lignin biosynthetic genes. Recent studies are taking into account the identification of these factors and how they interact to modulate the expression of target genes. Many transcription factors involved directly or indirectly in the biosynthesis of lignin regulation have been identified and characterized, including sugar cane and for our team. This paper aims to identify and characterize transcription factors that regulate lignin biosynthesis genes in two species of Saccharum, S. officinarum (producer of sucrose) and S. spontaneum (producer of fiber and known as energy cane), to the full exploitation of lignocellulosic fuels. They are CAD, F5H and COMT that are key in lignin biosynthesis. CAD influences the lignin content while F5H and COMT in the composition of this polymer. To achieve this goal several tools and/or strategies will be used: characterization of target promoters, analysis and expression profiling in silico databases available on the Internet and in our laboratory, analysis of coexpression, EMSA (electrophoretic mobility shift assay) in vitro testing of transgenic production, analysis model of transgenic plants, among others. (AU)