Comportamento diferencial dos níveis de metilação global da citosina entre genótipos de goiabeiras em um ciclo de produção

• Autor(a) principal: Alves, Luziane Brandão
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/10572
• topic: Guava; Gene expression; Production cycle; Goiabeiras; 5-mC; CLAE; Ciclo de produção; Melhoramento Vegetal; Expressão gênica; Goiaba - Cultivo; Genética vegetal; 631.523

The chromatin structure allows the gene content to be accessed according to its compaction degree. Modifications in chromatin condensation can be controlled by epigenetic mechanisms in eukaryotic organisms. Epigenetics is understood by changes in chromatin without altering the base sequence of the genetic material, resulting in modifications in gene expression, besides has strong environmental influence. There are different epigenetic mechanisms reported for others studies of which, DNA methylation consisting of the methyl group addition in the fifth carbon of the cytosine base, forming 5-methylcytosine (5-mC) has shown a notoriety in studies due to a higher amount of cytosines at the promoter regions of the genes. The overall methylation profile of cytosine may reveal epigenetic influence at different stages of development or of genotypes through the responses presented by organisms or some experienced factor. In this study, the guava - Psidium guajava L., a fruit from Myrtaceae family with nutritional, economic importance and of broad edaphoclimatic adaptation was studied. Plant development results in changes in organism responses throughout the life cycle and may be associated with epigenetic mechanisms. In the present study, the objective was to evaluate the 5-mC profile in adult guava trees at different stages of vegetative and reproductive development during a production cycle. Additionally, we studied the differential response of genotypes in relation to the 5-mC global profile, as well as its variation in different organs of the plant. The 5-mC percentage in 22 guava genotypes was quantified during five phases of the culture development by HighEfficiency Liquid Chromatography and later carried out studies in the differential organs through the genome global analysis. In the general averages analysis after quantification, there was no significant difference in the overall 5-mC profile between developmental phases. However, for vegetative stages (Post-pruning and Postharvesting) was observed values with more variation in the percentage of 5-mC when it was compared with the reproductive phases (flowering, fruiting and harvesting) that presented more homogeneous values. Among the genotypes, was observed a variation of the general mean in the 5-mC content ranging from 16.34% to 26.19%, especially the Sassaoka genotype, which presented the highest percentage of 5-mC during the developmental stages, with the exception of the post-harvest period. It was possible to notice that ten guava genotypes interacted with the development phases analyzed. Considering the plant organs, no significant differences were found between them. The analysis of the global methylation profile in guava allowed to understand and detect epigenetic changes in DNA sequence due to different stages of development, as well as genotype-dependent variation, highlighting the importance of these mechanisms in guava phenotype, more pronounced in the vegetative phase