Avaliação funcional do promotor do gene anatrC de Aspergillus nidulans na planta modelo Setaria viridis

Abstract

The sugarcane is an important crop in the Brazil's economy, because plays an essential role for the sugar sector and biofuel. The cane bagasse is a rich source for the bioethanol obtention, an even infeasible process on the commercial level, if it considers the cost-benefit analysis. The development of viable alternatives for the cell-wall degradation in sugarcane, with no need of high temperatures and strong acids, could make economically viable the obtention of this biofuel without the need of increase of planting area. One of alternatives is the plant genetic engineering, with the controlled degradation of cell-wall at the end of the production cycle. Thus, the identification of promoters with regulated induction in plants is highly desirable for the obtention of transgenic plants containing controlled expression. This work was performed aiming to assess the efficiency of the atrC gene promoter in controlling the expression of the uidA gene (GUS) in a model plant, Setaria viridis. The promoter was isolated from the fungus Aspergillus nidulans, and was chosen due to its induction ability under low ethanol concentration, previously found in Andrade (2000). An initial in-silico gene expression analysis of the sequence of the atrC gene was carried out using the PlantCare program for identifying cis elements, which are present on regulated promoters, resulting in the identification of several elements in the promoter sequence. Subsequently were performed genetic transformation tests using a design containing the patrC: uidA promoter in Setaria viridis via Agrobacterium tumefaciens. After verification of transformed plants, experiments were performed for histochemical tests, and endogenous GUS activity in Setaria viridis. Experiments for optimization of these histochemical testings were also performed, from which was found a high endogenous activity under solution of the most acid pH. Once established optimal conditions, histochemical tests were performed for assessing the efficiency of the promoter in controlling the gene uidA expression in the presence of different chemical compounds. According to results, we found the effect of ethanol and cycloheximide in the induction of the atrC promoter on roots. Induction using ethanol was also found in the qPCR experiments.