Podridão radicular da mandioca causada por Phytopythium sp.: propagação, metodologia de inoculação e prospecção de genes de resposta.

Abstract

Cassava is one of the most dynamic agricultural products in the world, being cultivated in many countries, however your productive is affected by pathogens, mainly those witch cause root rot, with Phytopythium sp. Studies related with identification of genes in the interaction between cassava-P/?yto/?y//?7MOT sp. are not found in the literature. Therefore, the main objective of thesis was prospecting genes involved in the mechanisms of response of cassava to the agent that causes root rot. The thesis is divided in six chapter, the first does a general contextualization, in second chapter was identified genes related with cassava immunity that possess potential for combat against root rot pathogen, the third chapter discussed the potential of phytocystatin in the control of plant diseases caused by fungi. In the chapter four a search of the cassava genome was carried out by genes that will code phytocystatin and these were characterized in silico and compared phylogenetically with phytocystatin from other cultures. Chapter five is about the adaptations methodology of rapid propagation of cassava for obtainment of seedlings aiming at greenhouse studies, such as the inoculation of root rot agent in cassava plants. The sixth chapter presents the results aiming at the inoculation of root rot agent of roots in cassava plants. The adaptation of the rapid propagation method of cassava was effective in the production of seedlings for studies at the molecular levei of the interaction of cassava -Phytopythium sp. In total, nine genes involved in biotic stress response were investigated, of which seven presented differential expression pattems in the roots inoculated with Phytopythium sp. The analysis of the cassava genome resulted in the identification of novel phytochemical gene isoforms that are distributed on seven chromosomes. These genes become eligible for use in breeding programs aimed at combating root rot in cassava caused by Phytopythium sp. Key