Banca de DEFESA: ERIKA DA COSTA FERNANDES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ERIKA DA COSTA FERNANDES
DATE: 29/10/2021
TIME: 09:00
LOCAL: Webconferência
TITLE:

Characterization of transport proteins involved in the Remobilization of Nitrate accumulated in vacuole of Rice.

KEY WORDS:

Low affinity transporter, NPF, Oryza sativa, tonoplast transporters.

PAGES: 126
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Fisiologia de Plantas Cultivadas
SUMMARY:

The uptake and remobilization of nitrate (NO3-) in cells vacuoles is an extremely important strategy for nitrogen (N) supply to plant development due to variations in soil availability. The transport of this ion across the tonoplast is mediated by specific transport proteins still poorly understood. The identification of these proteins allows to elucidate NO3- accumulation process and outline strategies in order to increase the use efficiency of N. The aim of this study was to identify genes that encode transport proteins responsible for remobilization of NO3- accumulated in the vacuole in rice. Amino acid sequences potentially coding for NO3- transport proteins expressed in vacuole were selected from gene bank and a phylogenetic analysis performed. The relative expression response of these proteins against the NO3- flush was evaluated in an experiment with rice plants (var. Manteiga) in Hoagland nutrient solution with 5 mM N-NO3- for 30 days, the plants were subjected to N suppression for 72 hours, followed by resupply of N. The genes OsNPF7.8 and OsNPF5.13 were cloned, inserted into an overexpression vector and the genetic transformation of rice plants (var. Nipponbare) was performed via A. tumefaciens. Two more experiments were carried out similar to the initial with modification in cultivation time and harvest: OsNPF7.8 strains were cultivated in constant dose for 20 days and submitted to 72h of suppression followed by the resupply of the NO3- harvesting after the suppression and 24h after resupply. The strains OsNPF5.13 were cultivated at constant dose for 24 days and submitted to N suppression, performing sample collections 24 and 96h after suppression. A total of 71 genes were used in the phylogenetic tree that showed differentiation between the coding sequences of chloride channels (CLC), high affinity (NRT2) and low affinity (NPF) transporters with separation of 8 groups. Among the low affinity transporters, group III clustered sequences of the NPF5 family characterized as responsible of NO3- efflux from the vacuole in A. thaliana and group IV show NPF7 genes mostly characterized as acting in NO3- influx to vacuole in rice. The expression analysis showed that OsNPF5.12, OsNPF5.13, OsNPF5.15, OsNPF5.16sp1 and OsNF5.17 genes presented transcription induction in response to NO3- suppression associated with the increase of NO3- levels in plant and nitrate reductase (NR) activity, it indicates a relationship with nitrate efflux from the vacuole. On the other hand, the OsNPF7.8 gene showed greater response to resupply period, relating to ion influx. The overexpression of OsNPF5.13 gene had higher NR activity, increased ammonium, N-amino and soluble sugar contents, demonstrating an increase in the stability of N assimilation. While overexpression of OsNPF7.8 gene showed increased NO3- content in the root and NR activity, as well as increased ammonium and N-amino content in leaves, demonstrating changes in influx of NO3- in the roots.

BANKING MEMBERS:
Interno - 538.864.458-87 - JOSÉ IVO BALDANI - UFRRJ
Externo à Instituição - LUC FELICIANUS MARIE ROUWS - EMBRAPA
Presidente - 002.180.573-34 - MANLIO SILVESTRE FERNANDES - UFRRJ
Externa ao Programa - 2147409 - MARILENE HILMA DOS SANTOS
Externa à Instituição - RAFAELA ELOI DE ALMEIDA ALVES