Banca de DEFESA: MATEUS MOREIRA BERNARDES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: MATEUS MOREIRA BERNARDES
DATA: 30/10/2025
HORA: 14:00
LOCAL: Online via GoogleMeet: https://meet.google.com/wkd-wamx-apa
TÍTULO:

 

A FRESH LOOK TO AN ANCIENT TECHNIQUE: A CELLULAR PERSPECTIVE ON SEED PRIMING

PALAVRAS-CHAVES:

Dessication; priming; imbibition; drying; mitochondria; sorghum.

PÁGINAS: 100
GRANDE ÁREA: Ciências Biológicas
ÁREA: Botânica
SUBÁREA: Fisiologia Vegetal
ESPECIALIDADE: Reprodução Vegetal
RESUMO:

As one of the most urgent environmental challenges, climate change represents an issue of global concern as it imposes multifaceted pressures on food systems, long-term sustainability and economy. As seeds constitute the entry point of most of crops worldwide and considering that germination of them are sensitive to a broad range of stresses, strategies that look after enhancing the seeds quality and potential for successful germination are encouraged. In this context, seed priming represents one of the seed enhancement technologies (SETs) most used to achieve these goals. The technique relies on controlled hydration and subsequent drying of seeds to trigger metabolic pathways that can promote accelerated and synchronized germination and improved seed vigor. However, the physiological, biochemical, and cellular mechanisms of this phenomenon are yet to be fully understood. In this thesis, we look after elucidating some mechanisms behind the seed priming responsiveness. The first chapter consists of a review where we bring the main physiological alterations that justify the increase of both (i) germination synchronization, and (ii) stress tolerance mechanisms. It discusses the relationship between the hydration status of cells and the consequence of that in each seed priming phase. The second chapter encompasses a research paper that seeks to answer whether the priming-triggered mechanisms are affected when seeds are either in normal or stress conditions. At this second chapter, two cultivars of sorghum (Btx623 and RTx430) seeds were used. Germination parameters were evaluated at a range of temperature conditions, with two conditions used for the following evaluations: optimum range temperature for germination (25ºC) and low-temperature stress condition (10ºC). Different approaches were performed to address a cellular perspective for seed priming, including untargeted metabolomics, mitochondria electron microscopy, seed respiration along with the evaluation of germination performance using respiratory inhibitors. In sum, cultivars responded differently to the conditions, with BTx623 having a peak priming response at low temperature conditions, which was not seen in RTx430. This response overlaps with a differential profile of activation of metabolites in each priming stage, mitochondria dynamics and respiratory performance among the cultivars. These results suggest critical phases of priming in which the mechanisms are more prominent to be triggered, along with possible markers for the technique to be explored and ameliorated.

MEMBROS DA BANCA:
Presidente - ELISA MONTEZE BICALHO - UFV (Membro)
Externo ao Programa - JOSE MARCIO ROCHA FARIA - DCF/ESAL (Membro)
Externo à Instituição - KACILDA NAOMI KUKI - UFV (Membro)
Interno - VITOR DE LAIA NASCIMENTO (Suplente)
Externo à Instituição - TOSHIHIRO OBATA - UNL (Membro)
Externo à Instituição - THOMAS CHRISTOPHER RHYS WILLIAMS - UnB (Membro)
Externo à Instituição - SHAKIRA SHAIK - UKZN (Suplente)