Banca de QUALIFICAÇÃO: PAULA SIMONE ORTIZ BARROS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: PAULA SIMONE ORTIZ BARROS
DATA: 28/09/2015
HORA: 14:30
LOCAL: sala SS1 do dept. de Biologia Celular e Genética
TÍTULO:

The mobilization of oils and storage proteins is simultaneously modulated by sugars during seedling establishment in sunflower

PALAVRAS-CHAVES:

Helianthus annuus L.; sugar partitioning, source-sink relation, sugar signaling

PÁGINAS: 20
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

In vitro feeding experiments using sunflower seedlings were performed to investigate the modulatory effect of exogenous sugars on the mobilization of different reserves and the concomitant alterations on metabolite partitioning and activity of reserve-degrading enzymes. When 100 mM sucrose was added to the culture medium, the mobilization of both oils and storage proteins was delayed in the cotyledons. An equimolar mixture of glucose and fructose failed to mimic this response, but similar results were found using equimolar concentration of glucose or non-metabolizable glucose analogues. The establishment of a decreasing non-reducing sugar gradient from the roots to the cotyledons accompanied the sugar-induced delay of oil and storage protein catabolism. In addition, glucose and the non-metabolizable sugars mannose and 3-O-methyl-glucose were able to decrease the activity of lipases, acid proteases and amylases in the cotyledons. According to these results, exogenous sugars modulated the mobilization of the main reserves (oils and storage proteins) during seedling establishment in sunflower. This response was not specifically triggered by sucrose and was not exclusively due to sugar metabolic effects. The activities of different reserve-degrading enzymes are simultaneously modulated by exogenous glucose. A gradient of non-reducing sugars (probably sucrose) may play a part in long-distance signalling, indicating alterations of the source-sink relation.

MEMBROS DA BANCA:
Presidente - 1453487 - KATIA CASTANHO SCORTECCI
Externo ao Programa - 2257836 - PAULO SERGIO MARINHO LUCIO
Interno - 1507794 - RODRIGO JULIANI SIQUEIRA DALMOLIN