Banca de DEFESA: YARA NATANE LIRA DUARTE

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : YARA NATANE LIRA DUARTE
DATE: 23/02/2024
TIME: 15:00
LOCAL: Departamento de Química - Sala Auditório
TITLE:

METABOMIC STUDY OF PLANTS OCCURRING IN PERNAMBUCO FOR SUSTAINABLE CONTROL OF Plutella xylostella

KEY WORDS:

Insecticide; Pest control; Natural products; Chemical composition

PAGES: 96
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Química dos Produtos Naturais
SUMMARY:

Plutella xylostella is a pest that causes damage to Brassica production in Brazil and around the world. Its control is carried out by applications of synthetic insecticides, but due to the pest's ability to adapt and resist, larger and more frequent doses are increasingly necessary, resulting in several environmental problems. Alternatively, formulated with extracts and essential oils from plants such as Lippia gracilis, Ocimum basilicum var. minimum and Ocimum gratissimum, have been identified as potential natural insecticides. However, it is known that the chemical composition of these products from plants can vary according to external factors. In this way, an investigation with a metabolomic approach allows identifying the ideal condition to stimulate the production of bioactive compounds with potential insecticides. Thus, the objective of this work was to enhance, through simulated conditions of biotic and abiotic stresses, the production of bioactive metabolites in specimens of L. gracilis, O. basilicum and O. gratissimum. The stressed plants were analyzed using metabolomic techniques and their obtained oils were evaluated for their toxicity to control P. xylostella. The species were cultivated under controlled conditions, divided into groups and subjected to different stresses: Manual predation (PM), methyl jasmonate (MJ), methyl salicylate (SM), ultraviolet (UV), herbivorous predation (PH), water scarcity (EH), excess water (ExH) and no stress plants (Control). The oils were obtained through hydrodistillation. The chemical composition was determined by gas chromatography coupled to mass spectrometry (GC-MS). The results of the oils were analyzed using the statistical techniques of PCA, Heatmap and molecular network. Insecticidal activity was evaluated using the mean lethal concentration test (LC₅₀) and inhibition of the enzyme acetylcholinesterase (AChE). The PCA, Heatmap and molecular network studies highlighted qualitative and quantitative differences in the chemical composition of the oils. Carvacrol was the majority constituent in all L. gracilis oils, with a higher percentage under UV stress (64.12%). For the species O. basilicum, (E)-methyl-cinnamate was identified as the major constituent in all oils, with the exception of species stressed by PH (43.48%) and ExH (40.18%), which revealed methyl chavicol as majority constituent. For O. gratissimum oil, eugenol was the majority in all oils. However, a significant increase in the percentage of γ-himachalene was observed for UV-stressed species (21.23%). All oils showed insecticidal activity against P. xylostella. The oils also showed activity on the acetylcholinesterase enzyme, with emphasis on the oils stressed by PM from the species L. gracilis and O. gratissimum and the oil stressed by MJ from the species O. basilicum. Therefore, it was found that biotic and abiotic stresses cause quantitative and qualitative changes in the chemical composition of the EOs of the species studied and also differ in the insecticidal activities tested.

COMMITTEE MEMBERS:
Presidente - MARCILIO MARTINS DE MORAES
Interno - CLAUDIO AUGUSTO GOMES DA CAMARA
Interno - JOAO RUFINO DE FREITAS FILHO
Externo ao Programa - 2002989 - ANDRE AUGUSTO PIMENTEL LIESEN NASCIMENTO - UFRPE