Comparison of the structure and nucleotide sequences of vicilin genes of cocoa and cotton raise questions about vicilin evolution

Cocoa (Theobroma cacao ) seeds produce two abundant mRNA transcripts during mid to late development - the protein products of which may be constituents of chocolate flavor components. Approximately one-third of the abundant mRNA encodes a protease inhibitor (asp, abundant seed protease inhibitor); the other two-thirds encode a seed storage protein, cocoa seed vicilin (csv). The nucleotide sequence of a partial cDNA, and that of the gene covering the protein coding region of the vicilin, differ by only one nucleotide substitution which does not alter the amino acid at that position. A comparison of the sequences reveals the presence of five short, AT-rich introns of between 90 and 112 nucleotides.