PARTIAL AMINO-ACID-SEQUENCE OF ECP31, A CARROT EMBRYOGENIC-CELL PROTEIN, AND ENHANCEMENT OF ITS ACCUMULATION BY ABSCISIC-ACID IN SOMATIC EMBRYOS

ECP31, an embryogenic-cell protein from carrot (Daucus carota L.), was purified by sequential column-chromatographic steps and digested by V8 protease on a nitrocellulose membrane. The resultant peptides were separated by reverse-phased column chromatography and sequenced. The sequences obtained were 70-80% homologous to those of a late-embryogenesis-abundant protein (D34) from cotton (Baker et al., 1988, Plant Mol. Biol. 11, 227-291). The level of ECP31 in somatic embryos of carrot was increased by treatment of the embryos with 3.7.10(-6) M abscisic acid (ABA) for 48 h, and there was no change in this enhanced level for up to 192 h in the presence of ABA. No similar enhancing effect of ABA was observed on the level of ECP31 in embryogenic callus or segments of carrot hypocotyls. In an immunohistochemical analysis, ECP31 was found in epidermal tissue and in the vascular system of ABA-treated somatic embryos.