Banca de DEFESA: KELLYA FRANCISCA MENDONÇA BARRETO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : KELLYA FRANCISCA MENDONÇA BARRETO
DATA : 25/07/2018
HORA: 14:00
LOCAL: Sala Carl Peter von Dietrich - Departamento de Bioquímica
TÍTULO:

The role of CALMODULIN in plants

PALAVRAS-CHAVES:

Saccharum spp, Early flowering, Anatomy, protein interaction network.

PÁGINAS: 122
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
SUBÁREA: Biologia Molecular
RESUMO:

Sugarcane is one of the most important producing monocultures in Brazil as a source of first generation renewable biofuel, as well as sugar and other derivatives. The edaphoclimatic conditions of the Northeast region may disfavor their cultivation, affecting the plants to bloom early. This has a negative impact and may lead to a reduction in the production of alcohol and sugar. Molecular studies using genes involved in the flowering pathway is of extreme economic importance. In this work, the main focus it the role of the ScCAM sequence (Calmodulin sequence in sugarcane). This sequence was previously identified related to flowering process. In order to understand the possible association of this sequence to flowering process in sugarcane different approaches were used here. It was used bioinformatics, protein-protein interaction (two-hybrid assays), analysis of transgenic plants Nicotiana tabacum with the super-expression cassette in antisense orientation and histological analysis from apical meristem from sugarcane from production field. First, bioinformatics analyzes allowed us to verify the conservation of the nucleotide sequence by comparing the ScCAM sequence with the sequences of AtCAM (Arabidospis thaliana), which presented 99% identity. A phylogenetic tree was done using the coding nucleotide sequences (CDS). It was observed a high conservation of calmodulin in plants. Based on these results, a 3D modeling from the ScCAM sequence was done. This model was overlapped to the AtCAM 3D model for the 4AQR crystal. This overlapped showed the EF-hands motifs and the entire protein structure. This data allowed us to propose that ScCAM may be a functional protein. After that, an interaction network was done using the AtCAM7 sequence using Cytoscape. The Clusters obtained were enriched and it showed proteins that may be interacting as flowering induction as well as it had a role in the oxidation/reduction homeostasis. The two hybrids assays identified some clones and tow of these clones had homology to A. thaliana ribosomal proteins L31-1 and L19-1 (Uniprot access: Q9SLL7). These results suggest that the ScCAM protein may interact with ribosomal proteins. The transgenic plants having the overexpression cassete in antisense (ScCAM-AS) orientation showed an increase in the germinated potential of the transgenic seeds ScCAM-AS, an increase of inflorescence branches number and fruit. Furthermore, it was observed an increase of root hair when compared to transgenic plants having the empty vector (control) or wild-type plants.

For leaves, it was not observed any changes at morphometric parameters. The only modification that was observed for these plants were the height, inflorescence and fruits. In parallel, it was also analyzed the shoot apical meristem from sugarcane plant at production field using early and late-flowering cultivar. This analysis showed that the flowering induction may be happen 30-60 days before for early flowering cultivar. Similar results were observed for the transgenic plants. In this way, the results obtained here reinforce the hypothesis that the CAM sequence may be associated to the flowering process as well as stress signaling pathway by modification from physiological processes, then it may be remodeling apical and root meristems. Moreover, changing flowering time and protein interaction network. In addition, the results obtained with the two-hybrid system suggest that ScCAM may act together with the associated ribosomal 60S protein in the participation of the formation of ribosomal subunits by activating or inhibiting certain genes.

MEMBROS DA BANCA:
Externo à Instituição - CARLOS HENRIQUE SALVINO GADELHA MENESES - UEPB
Externo ao Programa - 2294466 - CRISTIANE ELIZABETH COSTA DE MACEDO
Externo à Instituição - DAIANE CRISTINA FERREIRA GOLBERT - UFRN
Presidente - 1453487 - KATIA CASTANHO SCORTECCI
Externo à Instituição - NATHALIA DE SETTA - UFABC