|Support type:||Scholarships in Brazil - Scientific Initiation|
|Effective date (Start):||September 01, 2019|
|Effective date (End):||August 31, 2020|
|Field of knowledge:||Biological Sciences - Biochemistry - Enzymology|
|Principal Investigator:||Ricardo Alcántara de la Cruz|
|Grantee:||Guilherme Moraes de Oliveira|
|Home Institution:||Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil|
Herbicide resistance is an accomplished fact in Brazil since the 1990s. Herbicide resistance can be conferred by biochemical, physiological or molecular mechanisms grouped into non-target site (NTS) or target-site (TS). Herbicide resistance confirmation is relatively easy through dose-response assays; however, determining which mechanism (s) is involved is complex and sometimes costly, because often requires sophisticated equipment or specific kits. Therefore, a complete characterization of the mechanisms is, in most cases, unfeasible; however, one can not arbitrarily disregard the participation of any of them. Assays such as the quantification of the initial concentration (basal activity) of the target enzyme and its inhibition rate (enzymatic activity) by the herbicide may help to deduce which is the main group of mechanisms (TRS or NTSR) involved in an herbicide resistance case. If basal and enzymatic activities are similar between resistant and susceptible plants, participation of TSR mechanisms can be discarded, i.e., the research may be focused on the characterization of NTSR mechanisms. Differences in basal or enzymatic activity confirm the participation of TSR mechanisms, so the research should be focused on characterizing mechanism of this group. In this project, the basal and enzymatic activity of 5-enolpyruvyl-shikimate-3-phosphate synthase (glyphosate target enzyme), isolated from weed populations collected in citrus and other crops of the State of São Paulo, previously confirmed as being resistant to glyphosate, will be assayed. These results will allow to discriminate which group of mechanisms, TSR or NTSR, must be characterized in each resistant population in future experiments.