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| Author(s): |
Fernando Henrique Correr
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2017-01-16 |
| Examining board members: |
Gabriel Rodrigues Alves Margarido;
Vinicius Augusto Carvalho de Abreu;
Monalisa Sampaio Carneiro;
Maria Carolina Quecine Verdi
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| Advisor: | Gabriel Rodrigues Alves Margarido |
| Abstract | |
Orange rust is a foliar disease that affects sugarcane, gaining importance among the main diseases of this crop. Caused by the biotrophic phytopathogen Puccinia kuehnii, it has been reported in several countries in South America, including Brazil. Understanding the behavior of this disease is very important in comprehending its mechanisms of infection. The purpose of this work is to evaluate the transcriptome, by RNA sequencing, of the sugarcane response to infection by P. kuehnii during the establishment of the disease. The biological material used corresponds to sugarcane leaves from susceptible cultivar SP89-1115, sampled at the time of spore inoculation (0 h), 12 hours post inoculation (hpi), 24 hpi, 48 hpi, 5 days and 12 days post inoculation of orange rust. After pre-processing the reads, we mapped approximately 800 million reads to a reference sugarcane transcriptome obtained from sequencing six different genotypes. Subsequently, we performed differential expression analysis: i) in an Analysis of Variance type test; ii) comparing each time after inoculation against 0 h and iii) by comparing adjacent times. By the latter strategy, most of the differentially expressed transcripts occurred at 12 hpi, 48 hpi and 12 dpi. Through functional enrichment analysis, processes related mainly to photosynthesis and oxidation were evidenced, which are important in metabolic maintenance and cellular signaling under perturbation. The temporal gene expression profiles of Gene Ontology-annotated transcripts, in turn, showed reverse repression and stimulus waves between the comparisons 12 hpi vs 0 h and 48 hpi vs 24 hpi. Through the second differential expression analysis we found evidence that the expression levels of the transcripts were similar between 0 h and 48 hpi. Therefore, P. kuehnni may have acted in the sense of repressing defense response pathways in the first hours following inoculation, disfavoring mechanisms of phytohormones signaling and lignin deposition in the cell wall. This sugarcane cultivar may have been harmed by the absence of recognition systems and/or in the control of pathogen effector proteins in order to have been modulated for fungal establishment, with evidence of partial reestablishment of cellular homeostasis at 48 hpi. (AU) | |
| FAPESP's process: | 15/17935-8 - Temporal gene expression profiles of sugarcane infected by orange rust |
| Grantee: | Fernando Henrique Correr |
| Support Opportunities: | Scholarships in Brazil - Master |