MOLECULAR STUDIES ON OSMOPRIMED SEEDS OF CAULIFLOWER - A PARTIAL AMINO-ACID-SEQUENCE OF A VIGOR-RELATED PROTEIN AND OSMOPRIMING-ENHANCED EXPRESSION OF PUTATIVE ASPARTIC PROTEASE

A partial amino acid sequence of a vigour-related protein, V-1, from c auliflower (Brassica oleracea L.) seeds was obtained, after isolation by two-dimensional gel electrophoresis and gas-phase microsequencing. The sequence was found to have high homology to soybean seed maturatio n proteins. However, the position of the sequence in the V-1 polypepti de suggests that the V-1 and soybean proteins have different polypepti de structures. An osmoprimed seeds cDNA library was constructed and ha s been screened by a cDNA probe derived from the V-1 sequence. Two cDN A clones with high homology to aspartic protease (EC 3.4.23) from barl ey grain were isolated. The expression of putative aspartic protease m RNA was found to be enhanced by osmopriming, however the clones were f ound to have no significant sequence homology to the V-1.