Banca de QUALIFICAÇÃO: MONIQUE MACEDO ALVES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MONIQUE MACEDO ALVES
DATE: 10/10/2023
TIME: 10:00
LOCAL: Sala 4 - IA/DFITO
TITLE:

Characterization and management of herbicide-resistant goosegrass (Eleusine indica)

KEY WORDS:

graminicides, glyphosate, proteomics, resistance monitoring

PAGES: 31
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Matologia
SUMMARY:

Crabgrass (Eleusine indica) is a problematic weed in agricultural systems. Crabgrass relevance has increased in recent years due to its adaptability to diverse climatic conditions and the species' biological characteristics. Additionally, a limited variety of available herbicide modes of action for grass species control has contributed to rise in the resistance cases. Over the last 20 years, three cases of herbicide resistance in crabgrass biotypes have been reported in Brazil. The latest case in 2017 revealed multiple resistance to key herbicides used in this species management, revealing the evolution of resistance over time due to selection pressure. Sophisticated resistance mechanisms are shown in crabgrass resistant biotypes, including enzymatic modifications and gene regulation, resulting in resistance to herbicides inhibiting the enzyme acetyl-coenzyme A carboxylase (ACCase) and the enzyme Enolpyruvylshikimate-3-phosphate synthase (EPSPs). Resistant E. indica biotypes exhibit various resistance mechanisms associated with or independent of herbicide action sites, potentially linked to morphological, physiological, and genetic variations within the species. It is believed that the genotypic and phenotypic diversity in crabgrass biotypes in the field leads to varying levels of herbicide control efficacy. Therefore, this study aims to provide detailed information on the genetic, anatomical, and molecular diversity of Eleusine indica biotypes, seeking more effective strategies to mitigate herbicide resistance in these plants. To achieve this goal, the first stage of the study involves selecting putative resistant biotypes based on plant survival after herbicide application and subsequent seed harvesting from surviving plants for more detailed assays with their progeny. Following biotype selection, progenies will be studied in assays involving anatomical characterization of morphometric parameters of plant parts using light microscopy; characterization, quantification, and qualification of proteomes accumulated or repressed in plant tissue of E. indica biotypes due to the application of EPSPs and ACCase-inhibiting herbicides, through protein extraction and quantification. Finally, quantifying genetic variability through endogamy coefficients, expected and observed heterozygosity, and mean polymorphic information content (PIC), mediating genotypic and/or phenotypic diversity through the calculation of the Shannon-Wiener diversity index (H’), and studying population diversity based on molecular data through analysis of molecular variance (AMOVA). Results are expected to shed light on the molecular and physiological mechanisms controlling resistance to the studied herbicides, supporting more efficient approaches to prevent resistance and to control resistant weed populations.

COMMITTEE MEMBERS:
Presidente - 2466219 - CAMILA FERREIRA DE PINHO
Externo ao Programa - 3058137 - LUIZ RICARDO DOS SANTOS TOZIN - UFRRJExterna à Instituição - NATALIA DA SILVA GARCIA