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| Author(s): |
Juan Pablo Portilla Llerena
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2021-10-01 |
| Examining board members: |
Paulo Mazzafera;
Renato Vicentini;
Igor Cesarino;
Maria Magdalena Rossi;
Elisson Antonio da Costa Romanel
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| Advisor: | Paulo Mazzafera |
| Abstract | |
Sugarcane bagasse is a promising raw material for the production of second-generation ethanol. Still, its use presents challenges since the biomass of this crop is lignified (~23%), limiting the saccharification process. One of the main approaches to overcome recalcitrance is the biotechnological modification of the regulators (Transcription Factors; TFs) of lignin deposition, aimed at altering the content or composition of lignin. The transcriptional regulation of lignin deposition has been more studied in Arabidopsis than in monocots, and very little or nothing is known in sugarcane. The present work aimed to identify and characterize transcription factors that regulate lignin biosynthesis enzymes in "Saccharum" spp. The isolation of promoters of genes of the lignin biosynthetic pathway (CAD8, F5H, and COMT) in Saccharum species allowed the identification of repressor and activator TFs. Information originated from a principal component analysis (PCA), Pearson correlation and based networks comparing expression of genes of the lignin biosynthesis, S/G ratio, lignin content, against the transcriptional profile of the TFs of both parents, indicated ShMYB85 and ShMYB58/63 as potential regulators of lignin biosynthesis in sugarcane. Such indication was supported with protoplast transactivation assays. To have functional evidence of the role of these TFs, transgenics plants silenced for these TFs were produced using Saccharum spp. cultivar SP-3280 hybrid. The characterization, reinforced by 2D-NMR analysis, revealed that Shmyb85 and Shmyb58/63 had similarities and differences in changes related to lignin content and composition, histochemical tests, gene expresión, and phenolic compounds content. Saccharification was more efficient in Shmyb85. It was observed that in Shmyb85 and Shmyb58/63 there were alterations in more than one cell wall polysaccharide (SCW), with ShMYB85 being a broader activator than ShMYB58/63, since the first precisely controls the pectin content. Our data emphasize the opportunities and challenges of using these TFs MYBs to redesign the cell wall for bioenergy purposes. The knowledge generated here is important to boost traditional sugarcane breeding practices and approaches technologies for using lignocellulosic biomass in the development of second-generation ethanol (AU) | |
| FAPESP's process: | 18/25058-5 - Identification and characterization of transcriptional factors that regulate the biosynthesis of lignin species Saccharum |
| Grantee: | Juan Pablo Portilla Llerena |
| Support Opportunities: | Scholarships in Brazil - Doctorate |