Banca de DEFESA: BRUNA MOREIRA FREIRE

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : BRUNA MOREIRA FREIRE
DATE: 05/11/2024
TIME: 09:00
LOCAL: Auditório 801 no 8º andar do Bloco B do Campus Santo André da Universidade Federal do ABC
TITLE:

Evaluation of the use of selenium nanoparticles for biofortification of rice grains

PAGES: 245
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Análise de Traços e Química Ambiental
SUMMARY:

Currently, a  considerable part of  the world's  population  does not have  access  to a balanced  diet,  raising  the  occurrence  of micronutrient  deficiency.  Food  safety  and nutritional quality are priorities  to  improve  the health status of  the global population. Selenium deficiency has been a worldwide concern, affecting approximately 1 billion people. Nanotechnology has been increasingly used in plant sciences, with engineered nanoparticles  showing  promising  results  as  fertilizers  or  pesticides.  Selenium nanoparticles (SeNPs) are  in general  less  toxic and more bioavailable  than  ionic Se and, therefore, their use for biofortification of food crops has attracted attention. Rice is a staple food consumed by half of the world’s population. Agronomic biofortification of rice using SeNPs shows potential for combating Se deficiency but further research on  SeNP-plant  interaction  is required  before  it can  be  effectively  used  to  improve nutritional quality.  In  this study, SeNPs were synthesized by a chemical method and widely characterized. A series of experiments were carried out to evaluate the impacts of  SeNP  application  on  agronomic,  chemical,  and  biochemical  parameters  in rice plants. These experiments included the application of SeNPs to rice plants at different growth stages,  the comparison of  the effects of Se  in the  ionic and nanoparticulate forms, and  the use of different  inductively coupled plasma mass spectrometry  (ICP-MS)-based techniques to elucidate the interactions between NPs and plants. A method for sizing the synthesized SeNPs in aqueous solution by single particle ICP-MS (SP-ICP-MS) was optimized. SP-ICP-MS was also used to track isotopically labeled SeNPs in rice tissues, diving further insights into the uptake, accumulation, and translocation of SeNPs in plants. In vitro bioassays with rice germinating seeds were carried out to determine the optimal concentration of SeNPs, which was 0.5 mg L-1. Bulk analysis of plant  tissues  by  ICP-MS  revealed  that  SeNPs  influenced  Se  accumulation  and translocation  in rice  seedlings,  as  well as  the  uptake  and  accumulation  of macro, micronutrients,  and  potentially  toxic  elements.  The  consumption  of  biofortified  rice grains could reach 100% of the daily Se requirements,  thus being a promising alternative to face Se deficiency. Finally, Se speciation was carried out in rice grains by  high-performance  liquid chromatography coupled  with  ICP-MS  (HPLC-ICP-MS), showing that, during their uptake by rice leaves and translocation to the grains, SeNPs are converted into less toxic, more bioavailable organic species. The results of the present study  indicate that  SeNP application  modulates  Se uptake, translocation, accumulation, and biotransformation  in rice plants differently from inorganic Se fertilizers, showing the feasibility of biofortification with SeNPs to produce Se-enriched rice.  The consumption of the  produced  biofortified  rice can be one  strategy  for sustainable agriculture to combat malnutrition while ensuring food security and safety.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 2046361 - BRUNO LEMOS BATISTA
Membro Titular - Examinador(a) Interno ao Programa - 1933328 - HELOISA FRANCA MALTEZ
Membro Titular - Examinador(a) Externo à Instituição - GONZALO RODRIGO TORTELLA FUENTES
Membro Titular - Examinador(a) Externo à Instituição - HALLEY CAIXETA DE OLIVEIRA - UEL
Membro Titular - Examinador(a) Externo à Instituição - JULIANA NAOZUKA - UNIFESP
Membro Suplente - Examinador(a) Externo à Instituição - BRUNO ALVES ROCHA - UNIFAL-MG
Membro Suplente - Examinador(a) Externo à Instituição - MARIA FERNANDA HORNOS CARNEIRO - UNESP