Proteins related with embryogenic potential in callus and cell suspensionsof sugarcane (Saccharum sp.)

Previous results have shown that some proteins secreted in the culture medi um are involved with the formation of embryogenic cells and can modify soma tic embryo differentiation. Undifferentiated cell suspensions grown in the presence of 13 muM 2,4-dichlorophenoxyacetic acid (2,4-D) and obtained from embryogenic and non-embryogenic callus were used to study these events in sugarcane plants (ev. PR-62258). The cell suspension growth curves were det ermined and soluble proteins were extracted from embryogenic and non-embryo genic callus and culture medium from cell suspensions. In embryogenic callu s we detected 1.43 times more protein than in non-embryogenic callus and th e electrophoretic protein patterns show specific polypeptides for both call us types. In embryogenic callus we detected a cluster of four polypeptides in the range of 38-44 kDa and another polypeptide of 23 kDa that were not o bserved in non-embryogenic callus. In nonembryogenic callus there is a 35-k Da. polypeptide that was not detected in embryogenic callus. In the case of extracellular proteins, the medium from embryogenic cell suspensions conta ined four polypeptides of 41, 38, 34 and 28 kDa that were slightly detected in the medium from non-embryogenic cell cultures; we also detected a band at 15 kDa that could not be observed in the medium from non-embryogenic cel l suspensions. These results suggest that the development of embryogenic ca llus and cell suspensions is related to the type and amount of intracellula r proteins in the Callus cells and to the secreted proteins from these cell s into the medium.