Biosynthesis of lignin in sugarcane under drought and cold stresses

• Grant number: 11/17081-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2011
• End date: October 31, 2012
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal Investigator: Paulo Mazzafera
• Grantee: Bruno Henrique Pereira
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 08/58035-6 - Control of lignin biosynthesis in sugar cane: many gaps still to be filled, AP.BIOEN.TEM

Abstract

Lignin is one of the most important factor limiting the use of plant lignocellulosic material to produce ethanol. Lignin biosynthesis pathway is a complex network and several attempts to change lignin gene expression led to diverse and undesirable impacts on plant physiology. Although significant knowledge on lignin in plants has been obtained, we still do not know to which extent plants can survive without this polymer. Therefore, a challenge to use lignocellulosic feedstocks to produce ethanol would not simply consist in reducing lignin content but will also need to consider changing its structure in such a way that it could be more easily removed from biomass without compromising the polymer strength allowing plants thrive normally. Lignin content may vary in response to several biotic and abiotic stresses and understanding how this occurs may help to understand the control of lignin biosynthesis. We know "almost nothing" about lignin in sugarcane. However, taking in account the information accumulated for other plants and the agronomical practices and problems in sugarcane cultivation, we may have enough hints to plan several studies on how sugarcane modulates lignin composition and content. Therefore, the aim of this project is 1) to cultivate contrasting sugarcane genetic material for lignin content in 5 locations well characterized for temperature, water availability and irradiance and analyze lignin, sucrose and cellulose, and then, based on these results to study gene expression and perform a more detailed study of lignin composition; 2) to search the SUCEST database for ESTs coding transcription factors known to be involved in lignin metabolism in model plants and use this information in controlled studies (on water supply, nitrogen fertilization, light intensity and low temperatures under field and greenhouse conditions, and growth chamber) to establish correlations between transcription factors regulation and lignin content; 3) search the SUCEST database for ESTs coding ortologs to peroxidases and laccases and use this information in the controlled studies to evaluate the involvement of these enzymes in lignin biosynthesis; 4) to perform a system biology study of regulatory network involved in lignin biosynthesis. With this information we may get some valuable knowledge on the lignin biosynthesis in the complex sugarcane genome. (AU)