Poster: Proteomics

Abs # 966: Aleurone membrane proteins: comparison of two-dimensional electrophoretic patterns from contrasting vigor seeds

Presenter:	Maya, Vanessa R., van@correo.unam.mx
Authors	Maya, Vanessa R. (A)   Camacho, Karla A. (A)   Bernal-Lugo, Irma O. (A)
Affiliations:	(A): Universidad Nacional Autonoma de Mexico, Departamento de Bioquimica

Vigor, defined as the capability of a seed to establish itself as an autotrophic organism, depends partly on the efficiency of reserve mobilization during germination and varies among different seed lots. In cereals, gibberellic acid (GA₃) controls reserve mobilization. In order for this process to succeed, it is necessary that the aleurone membrane systems are complete and fully functional; since many of the events involved in the response to GA₃ take place there. Because most of the dynamic functions of membranes depend on proteins, it is possible that in low vigor seeds some of the physicochemical characteristics of aleurone membrane proteins change; since during seed aging in storage: vigor decreases, membrane organization changes, and also there is an impairment in the reserve mobilization process. Therefore, the objective of this work was to evaluate the differences between the electrophoretic two-dimensional (IEF/SDS-PAGE) patterns of membrane proteins of control (1998) and aged (1974) barley aleurone layers. Microsomal fraction was isolated from control and aged aleurones incubated with or without GA₃. Membrane proteins were extracted and solubilized for their separation by IEF/SDS-PAGE. The electrophoretic 2D membrane protein patterns of control and aged seeds presented differences mainly in the region of 48-55 KDa in the pI range of 4.8-6.3, and in molecular weights under 16 KDa in the pI range of 4.6-5.6. These results suggest that membrane proteins from low vigor seeds might undergo changes which affect their reserve mobilization capacity. In the future, it will be necessary to identify the proteins which are important for reserve mobilization.