Utilização do silenciamento gênico e nanotecnologia para o controle do mofo branco e da podridão negra

Abstract

Brassica oleracea consists in a culture of high economic and food importance, being the most cultivated brassica in Brazil. Among diseases that affect this culture, we can highlight black rot and the white mold. In this work, strategies for the control of these diseases were developed using gene silencing associated or not with nanostructures. In order to control black rot, the expression of genes involved in Xcc pathogenicity using in vitro and in vivo systems was evaluated. The presence of plant extract in the in vitro system resulted in an expression profile similar to that observed in vivo, being effective in the study of pathogenicity mechanisms in Xanthomonas. Five of these genes were selected as targets for gene silencing. To evaluate the occurrence of gene silencing by HIGS in Xanthomonas, bacteria were transformed with the uidA gene and inoculated into transgenic plants able to silence this gene. The results indicated the occurrence of gene silencing in bacteria. Furthermore, aiming to obtain a method for the nucleic acid delivery into the bacterial cell, we developed a nanostructure evaluated in Escherichia coli. The pPM7g vector containing the gfp gene was complexed with liposomes. The assays showed the occurrence of transport of nucleic acids into the bacterial cell through the nanostructures developed. In order to control white mold, three effector genes were selected as targets using HIGS. Arabidopsis thaliana plants were transformed by floral dip and 3 transgenic lines were obtained for each gene. The results obtained in this work showed that the strategies used have a high potential to control phytopathogens, and can generate biotechnological products efficient in the control of plant diseases.