The invention provides novel regulatory polynucleotide sequences useful in plant genetic engineering applications, e.g., polynucleotides having transcriptional promoter or terminator activity, are provided. The invention also provides novel gene and polypeptide sequences, for example, genes corresponding to pineapple carotenoid biosynthesis proteins, e.g., carotenoid isomerase (ISO), phytoene synthase (PSY) and lycopene .beta.-cyclase (LYC), which find use in producing plants with improved traits, e.g., improved nutritional value. In addition, related nucleic acids, e.g., vectors, and transformed plants that include one or more of these polynucleotides or polypeptides are also provided, as are related methods for producing such compositions.