Banca de QUALIFICAÇÃO: ERIKA DA COSTA FERNANDES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ERIKA DA COSTA FERNANDES
DATA : 10/07/2019
HORA: 09:00
LOCAL: Sala 1 do PPGF
TÍTULO:

Characterization of Nitrate Carriers Involved in the Remobilization of Nitrogen stored in the Vacuum in Rice

PALAVRAS-CHAVES:

Low affinity transporter, NPF, Oryza sativa, tonoplast transporters

PÁGINAS: 30
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Fisiologia de Plantas Cultivadas
RESUMO:

The uptake and remobilization of nitrate in cells is of extreme importance for nitrogen supply. The identification of transport proteins that perform these processes, allows to elucidate how the genes involved in this pathway works and, allowing to outline strategies in order to increase the use efficiency of this nutrient. The aims of this study are to identificate and characterize the carrier proteins responsible for remobilization of nitrate accumulated in vacuole. An experiment was carried out to evaluate the kinetics of nitrate absorption. Plants were cultivated for 30 days in a nutrient solution containing 5 mM N-NO₃^-, then were submitted to a 72-hour period without nitrogen supply, after this time the nitrogen was resupplied. Plant tissue were harvested every 24 hours in the N-suppression period and then harvested at 3, 6, 24 and 72 hours after N resupply for analysis of the metabolism and gene expression. A total of 71 genes were analyzed to develop a phylogenetic tree that clustered into three large groups. The third group assembled genes of NPF family, and was subdivided into 6 subgroups. Subgroup 6.3 contained Arabidopsis genes responsible for efflux nitrate from vacuole and Rice genes of NPF5 family that were selected for expression analysis. Subgroup 6.4 clustered NPF7 family genes including the NPF7.2 gene, responsible for the influx of nitrate in the vacuole, also selected for expression analysis. The time course analysis (72 hours) of nitrogen suppression was not enough to consume all the nitrate storage in plant tissues. According to the results, sheath tissue was the organ responsible for accumulation and translocation of nitrate. Nitrate content decreased with more intensity as the suppression periods increased and there were no significant levels of nitrate reductase enzyme activity at any analyzed time. Expression analysis demonstrated that OsNPF5.12, OsNPF5.13, OsNPF5.15, OsNPF5.16a and OsNF5.17 genes showed increased expression levels in response to nitrogen suppression indicating a possible relationship with nitrate efflux. The OsNPF7.1, OsNPF7.7 and OsNPF7.8 genes presented a higher response during resupply period, which may be related to nitrate influx to the vacuole.

MEMBROS DA BANCA:
Presidente - 002.180.573-34 - MANLIO SILVESTRE FERNANDES - UFRRJ
Interno - 1712769 - PEDRO CORREA DAMASCENO JUNIOR
Externo ao Programa - 1809123 - ANDRE MARQUES DOS SANTOS
Externo à Instituição - MARCIA SOARES VIDAL - UFRJ