Banca de DEFESA: ANDRÉ LUIS DA SILVA PARENTE NOGUEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDRÉ LUIS DA SILVA PARENTE NOGUEIRA
DATE: 27/08/2024
TIME: 13:00
LOCAL: videoconferência
TITLE:

Characterization of osef gene and its relation with drought tolerance in rice.

KEY WORDS:

 

Plant Ecophysiology, Elongation Factor 2, Plant Transformation, Overexpression, Gene Expression, CRISPR/Cas9, Genetically Modified Organisms (GMOs).

PAGES: 100
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:

As the abiotic stress with the greatest impact on plants, drought is a key factor to be studied in agriculture. In plants, drought affects processes such as photosynthesis, respiration, and cellular metabolism, impacting growth and production. Despite this, plants, as sessile organisms, have developed mechanisms to tolerate drought by modulating their genetic machinery, leading to the expression of genes that code for proteins that enable survival under water restriction. In this context, there are genes whose functions are not yet characterized, necessitating further understanding. This research aims to identify and characterize differentially expressed genes in response to drought, with a special focus on the Elongation Factor 2 gene (OsEF2), to understand its role in drought tolerance in rice plants. Following the hypothesis that the OsEF2 gene is involved in drought tolerance, rice lines were transformed at the Laboratory of Plant Mineral Nutrition (LNMP) of the Federal Rural University of Rio de Janeiro (UFRRJ). Lines were selected for overexpression and knockout of this gene. F2 generations of rice plants were used for the experiments. After applying water suspension treatment and a control, with 8 repetitions each, the experimental units (knockout, EF15, EF18, EF19, and WT) were subjected to drought and evaluated over three weeks for evapotranspiration, developmental aspects, color, and chlorophyll fluorescence. Under field capacity below 15%, they were assessed for photosystem integrity and rehydrated for subsequent productivity and final plant development analysis. Complementary experiments were conducted on plant lines subjected to Polyethylene Glycol (PEG) to analyze electrolyte leakage, relative water content, and root morphological aspects over a week of 20% PEG treatment. After water suspension, OsEF2 plants required less water for development and exhibited lower senescence patterns through color segmentation; they also presented photochemically active reaction centers and indications of better CO2 use efficiency. Under drought conditions, OsEF2 plants also demonstrated better leaf temperature regulation, chlorophyll integrity, and higher ATP synthesis compared to WT plants. The OsEF2 gene knockout did not allow in-depth evaluations as it produced stunted plants with almost 100% abortion rates. The Elongation Factor 2 gene gives a drought escape strategy, allowing plants to achieve better water use efficiency, ensuring better integrity and activity of the photosystem after water suspension.

COMMITTEE MEMBERS:
Externo ao Programa - 1809123 - ANDRE MARQUES DOS SANTOS - nullInterno - 1399485 - ANDRES CALDERIN GARCIA
Presidente - 2626406 - LEANDRO AZEVEDO SANTOS
Externo à Instituição - MARCUS VINICIUS LOSS SPERANDIO - UFRPE
Externo à Instituição - VINICIUS MIRANDA DE SOUZA - IFRR