ShF5H1 overexpression increases syringyl lignin and improves saccharification in sugarcane leaves

Author(s)

Portilla Llerena, Juan Pablo ; Kiyota, Eduardo ; dos Santos, Fernanda Raquel Camilo ; Garcia, Julio C. ; de Lima, Rodrigo Faleiro ; Mayer, Juliana Lischka Sampaio ; dos Santos Brito, Michael ; Mazzafera, Paulo ; Creste, Silvana ; Nobile, Paula Macedo

• Document type: Journal article
• Source: GM CROPS & FOOD-BIOTECHNOLOGY IN AGRICULTURE AND THE FOOD CHAIN; v. 15, n. 1, p. 18-pg., 2024-12-31.

Abstract

The agricultural sugarcane residues, bagasse and straws, can be used for second-generation ethanol (2GE) production by the cellulose conversion into glucose (saccharification). However, the lignin content negatively impacts the saccharification process. This polymer is mainly composed of guaiacyl (G), hydroxyphenyl (H), and syringyl (S) units, the latter formed in the ferulate 5-hydroxylase (F5H) branch of the lignin biosynthesis pathway. We have generated transgenic lines overexpressing ShF5H1 under the control of the C4H (cinnamate 4-hydroxylase) rice promoter, which led to a significant increase of up to 160% in the S/G ratio and 63% in the saccharification efficiency in leaves. Nevertheless, the content of lignin was unchanged in this organ. In culms, neither the S/G ratio nor sucrose accumulation was altered, suggesting that ShF5H1 overexpression would not affect first-generation ethanol production. Interestingly, the bagasse showed a significantly higher fiber content. Our results indicate that the tissue-specific manipulation of the biosynthetic branch leading to S unit formation is industrially advantageous and has established a foundation for further studies aiming at refining lignin modifications. Thus, the ShF5H1 overexpression in sugarcane emerges as an efficient strategy to improve 2GE production from straw. (AU)

• FAPESP's process: 14/23017-9 - Identification of target genes regulated by the SHINE transcription factor in monocot plants
• Grantee: Michael dos Santos Brito
• Support Opportunities: Scholarships in Brazil - BIOEN - Young Researchers
• FAPESP's process: 13/19214-0 - Sugarcane gene functional analysis in transgenic rice and lignin modified sugarcane in order to cellulosic ethanol production
• Grantee: Paula Macedo Nobile
• Support Opportunities: Research Grants - Young Investigators Grants