Contribuição para o estudo dos mecanismos de resistência ao glifosato em Conyza canadensis

• Author(s): Domingos, David Marciano da Conceição
• Date: 2014
• Persistent ID: http://hdl.handle.net/10400.5/8273
• Origin: Repositório da UTL
• Subject(s): resistance; glyphosate; Conyza canadensis; shikimate; EPSPS
• Document Type: Master thesis
• Language: Portuguese
• Advisor(s): Monteiro, Ana Maria da Silva; Calha, Isabel Maria Miranda
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Engenharia Agronómica - Proteção de Plantas - Instituto Superior de Agronomia

This dissertation reports the study of two resistance mechanisms in a glyphosate-resistant Conyza canadensis population (B15), comparatively with a susceptible population (B), from intensive olive orchards in Alentejo (south of Portugal). Initially, the presence of resistance was confirmed by a shikimate leaf disc assay. Then, the sequence of the gene encoding the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) was determined and, lastly, were analysed the expression levels of the gene encoding this enzyme. The shikimate leaf disc assay showed a higher accumulation of shikimate in the population B, relatively to population B15, 24 hours after being exposed to glyphosate. The EPSPS-2 cDNA sequencing didn’t reveal differences in enzyme’s constitution between the two populations. The analysis of gene expression also revealed no differences in expression levels of this enzyme, 24 hours after glyphosate application. These results suggest that the studied population has no EPSPS enzyme mutation or overexpression as a mechanism of resistance to glyphosate