Programa de Pós-graduação em Ciências Biológicas

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Navegando Programa de Pós-graduação em Ciências Biológicas por Por Orientador "Brondani, Claudio"

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    Expressão de genes de arroz homólogos a genes de arabidopsis relacionados à produtividade de grão
    (Universidade Federal de Goiás, 2015-08-06) Oliveira, João Augusto Vieira de; Brondani, Claudio; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4780817T7
    Evidences indicate that by 2030 an increase in 40% of rice production is necessary so that it can meet the demand of the world population. The aim of this study was to quantify the expression of rice genes homologs to Arabidopsis genes previously related to yield (RUBISCO, AVP1, DA1 and TOR) by RT-qPCR analysis. The genotypes used in the study were the upland rice cultivars BRSMG Curinga and Primavera, and the old variety Douradão, which were evaluated in a yield experiment under two soil fertility levels, in a factorial scheme, in completely randomized design with two replications. Plant tissue samples were collected in vegetative and reproductive stages, which were used for total RNA isolation and subsequent cDNA syntheses. The cDNA was then subjected to RT-qPCR to evaluate the expression of four genes studied. Significant differences were observed in the expression of RUBISCO gene in leaves of upland rice plants in the vegetative stage, where there was a higher expression in high-level fertility in the soil, while in the reproductive stage, there was a higher expression in the low fertility treatment. DA1 that negatively regulates cell proliferation was less expressed in the vegetative stage in the treatment with high level of fertility, suggesting the suppression of this gene. AVP1 was more expressed in the reproductive stage, probably in order to increase the availability of P in a fundamental phase for the formation of the grain. TOR was the most expressed gene in this work, with a greater expression in adequate conditions of fertility, confirming its action under favorable conditions of cultivation. This study indicates that even two species that diverged over 120 million years have conserved productivity related metabolic routes. Thus, genes previously studied and validated in the model species Arabidopsis and that are of interest to economically important crops such as rice, may be the starting point for the development of cultivars with higher performance and better agronomic traits.
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    Análise do transcriptoma de arroz de terras altas (Oryza sativa L.) cultivado sob condição de seca
    (Universidade Federal de Goiás, 2014-03-31) Silveira, Ricardo Diógenes Dias; Brondani, Claudio; http://lattes.cnpq.br/4775600104554147
    The upland rice is sensitive to drought especially during the reproductive phase, when even moderate stress can result in drastic reduction in yield. Upon the occurrence of the drought a variety of genes is induced in plants, triggering a complex network of responses that extends from the perception and recognition of sign of stress, through activation of adaptive response genes. The objective of this thesis was to study the transcriptome of two Brazilian cultivars of upland rice (Douradão and Primavera) contrasting in relation to drought tolerance, and subjected to two experiments under water deficit in two consecutive years. In the first year, corresponding to Article 1, the transcripts from leaf samples were sequenced by RNA-seq, and in the second year, corresponding to Article 2, the transcripts from leaf and root samples were sequenced, for both cultivars, under normal and limited irrigation during the reproductive phase. In Article 1, the sequencing showed in Douradão 27,618 transcripts, from which 24,090 (87.2 %) showed homology to rice genes and 27,221 transcripts in Primavera, from which 23,663 (86.9 %) showed homology to rice genes. Douradão had 493 diferentially expressed genes (DEGs) and Primavera 1,154 DGEs. In Article 2 it were identified 44,978 and 37,898 transcripts in leaf and root tissues, respectively. Douradão showed 3,554 and 840 diferentially expressed genes (DEGs), in leaf and root tissues, respectively, while Primavera showed 1,141 and 1,975 DEGs on those tissues, respectively.It were identified genes from different metabolic routes related to distinct drought tolerance mechanisms in leaf and root tissues, such as cell signaling -related genes, transcription factors, functional protective proteins and cell cellular detoxification enzymes. A set of expressed genes from both tissues were validated by RT–qPCR and most of them were similar to the results of RNA-seq results. The rice transcripts not annotated were submitted to an orthology analysis in relation to the Arabidopsis thaliana databank, which revealed one gene related to the root cell growth Douradão. The 16 genes validated by RT-qPCR will be used as molecular markers for marker assisted selection in the upland rice breeding program and are candidate genes for use in transformation of rice cultivars susceptible to drought.